riot

I own a 1993 del Sol S (D15B7) with approx 148,000 miles. This is my daily driver.

I have owned it for just over a year and have never had anything major go wrong with it. I change the oil every 3k, have replaced the air filter, fuel filter, and spark plugs. Recently I have been having problems starting the car. I live in Texas, and the heat is intense. It seems to only happen after the car has sat in the sun ALL DAY. It used to take three tries to start it, now it takes slightly more. It will crank and crank and crank but not actually fire up. I know its not the starter because Im not hearing any unordinary noises. I checked all of the connections and everything seems fine. Once the car starts it runs FINE with no problems. This rules out several things.

So everybody keeps telling me about "vapor lock" and thats what the problem is since it ONLY happens after sitting in the heat ALL DAY. So today I drove my other car and got home to a del sol that has been sitting in the sun all day. I try to start it and sure enough...same thing. So I popped the gas door cap, loosen the gas cap...*pppppsssssssssshhhhhhhhhhhhhhhhhhhhhhhhhhhh !!!* ...go to start it, *BAM*...fires RIGHT up!

So is this my solution? Now what do I do to avoid this?

-ryan

slowpokesi

never heard of that ****

riot

thanks for the helpful reply!

barton

Just loosen the gas cap and retighten it! Problem solved.

riot

TTT

B18C5-EH2

I think you are experiencing a big coincidence when you pop your gas cap and then it fires right up.

I think you need a new main relay.

The main relay is a little reddish borwnish box inside of a grey plastic sleeve/case near your hood release lever under your dash.

That's where it is in the 1992-1995 Civic, so it's probably there in your Sol too. I've honestly never looked.

It turns your fuel pump on, so when it's not working right it will let the engine spin over, but not crank.

Over the years of extreme heat (like in Texas) the soldered connections on the back begin to crack and when hot they don't make contact to function correctly.

The part is like $50.00 from the dealer.

Part number:

39400-SM4-003

This is the most common problem associated with a car sitting for a bit in the heat and then not cranking.

You're probably just psyching yourself out with the whole gas cap ****.

riot

I'll keep that in mind and if the problem persists, I will replace that relay. I priced it out to be like $42.

I'll see what happens today.

-ryan

93CivicSI

Replace the main fuel relay.

slowpokesi

yeah thats what i told u the other day numbnutz,

anyhow if you have a soldering gun you might be able to fix it your self by opening it up and resoldering the connections,

hahaha maybe mugenfag has one

if that doesnt do the trick, drill a big hole in ur gas cap

EH339

Hi riot! Wow, alotta Texans in this thread.... lol!


And back on topic, good luck with your car. I saw a really sweet red 93 del sol at my old dealership yesterday. Only 56K miles miles on it!

ill phil

Yeah, like Tom said. It's the main relay. I think everyone in Texas has had that problem. Oh yeah, they say vaporlock is only myth on old school carburated cars by the way

Nikos

vapor lock can also be found in fuel injected cars with high pressure fuel pumps...


My 89 volvo drove me nuts with it. A pressure release valve that was part of the fuel pump was not always shutting off. So by me cranking the car a few times, I was able to rebuid that pressure in the fuel line.

But in Hondas I am sure it is not a high pressure fuel pump.

ill phil

Hmm... didn't know that. Must be pretty damn rare then. In school they taught that vaporlock wasn't really a problem with fuel injected cars and most people assumed from the old school days that with a fuel problem pressure related it was vapor lock. But I can guarantee you got me beat on Volvo info

Nikos

Since this a tech board, I figure you can benefit by reading this

DIAGNOSING FUEL PUMPS: Bosch EFI Pump Technology, Larry Carley, ImportCar, April 1999
Compared to carburetion, fuel injection is a much better method of delivering fuel because it doesn’t need intake vacuum to siphon fuel through metering orifices. Fuel is sprayed directly into the intake ports under high pressure through the injectors. This improves fuel atomization for crisper throttle response, better performance and fuel economy. It also makes cold starting easier, improves idle quality while the engine is warming up and allows for cleaner emissions.

However, to achieve these benefits, all fuel injection systems require an electric pump that can deliver a steady supply of fuel under much higher pressures than those needed for a carburetor. A typical carbureted engine needs very little pressure in the fuel line to move gas from the fuel tank to the carburetor. A carbureted Honda Civic, for example, only needs about 1.3 to 2.1 psi (0.1 to 0.15 bar) of fuel pressure. A carbureted engine with a larger V6 or V8 engine might require 4 to 6 psi (0.3 to 0.4 bar).

A typical fuel-injected engine, on the other hand, may require anywhere from 30 to 90 psi (2 to 6.3 bar) of fuel pressure, depending on the application. The pressure specifications will vary according to the type of fuel injection system on the engine as well as the performance, fuel economy and emission requirements of that particular vehicle. There are no rules of thumb. Every application is different, so always look up the pressure specs when troubleshooting fuel-related performance problems.

For instance, a number of late-model Audi, BMW and Volkswagen vehicles have Bosch Motronic fuel

injection systems. Audi says a 1995-’96 2.8L V6 requires 55 to 70 psi (3.8 to 4.2 bar) of static pressure with the engine off and no vacuum to the regulator, or 48 to 63 psi (3.3 to 3.7 bar) with the engine idling and vacuum present at the regulator. BMW only needs 35 to 52 psi (2.4 to 3.6 bar) of static pressure with the engine off. A Volkswagen GTI 2.0L calls for 87 to 94 psi (6.1 to 6.6 bar) of static pressure (engine off), while a Jetta with a 2.8L VR6 needs 50 psi (3.5 bar).

The method for checking fuel pressure will also vary depending on the application. On many European Bosch applications, fuel pressure is checked statically with the engine and ignition off, and the fuel pump relay disabled. Before hooking up your pressure gauge, you should relieve all pressure in the fuel system. This can be done by disconnecting the pump’s relay or fuse, starting the engine, letting it run until it stalls, then cranking it an additional 10 seconds to bleed off any remaining pressure.

Once all the pressure in the system has been relieved, you can tee your gauge between the fuel supply line and fuel rail, hook it directly to the test connector on the fuel rail (if one is provided), or connect it between the test port on the fuel distributor and cold start injector supply line (KE-Jetronic systems).

On many Bosch applications, the test specs are for static pressure with the engine off. Some also provide a second spec for system pressure with a hand vacuum pump attached to the regulator to simulate intake vacuum at idle. You have to use jumpers to bypass the relay and power the pump for a static pressure test. But, if the system has a test connector on the fuel rail and you’re checking dynamic pressure with the engine running (such as on a 1992 or newer Porsche 968 with Motronic), just start the engine and let it idle to check the system pressure.

On some applications, you will also find a spec listed for maximum system pressure with the fuel return line temporarily clamped shut. This would indicate the pump’s maximum output pressure, which may be as much as double the system’s normal operating pressure. On a 1989-’92 Volvo 740 with a 2.3L engine and Bosch LH-Jetronic, the normal system pressure is 43 psi (3 bar), but the maximum deadhead pressure with the return line pinched shut is 85 psi (6 bar).

PRESSURE PROBLEMS
So what happens if fuel pressure is not within specs? Too much pressure will create a rich fuel condition, causing an increase in fuel consumption and carbon monoxide (CO) emissions. An engine that’s running really rich may also experience a rough idle, surging and possibly even carbon fouled spark plugs.

The more common problem, though, is not enough pressure or no pressure at all.

No pressure will obviously prevent the engine from starting, but, if there’s enough pressure in the system, the engine may start and idle but run poorly. Without normal pressure feeding the injectors, the amount of fuel delivered is reduced, creating a lean condition. Symptoms may include a rough idle; stalling; hesitation or misfire on acceleration; a lack of normal power; and elevated hydrocarbon (HC) emissions because of lean misfire at idle or under load.

If there’s little or no pressure in the system, the engine will crank normally but won’t start. So, if the engine has spark and compression but refuses to start, the underlying cause may be a dead fuel pump, a defective pump relay, wiring problem, blown fuse, plugged fuel filter, plugged supply line, clogged fuel pickup sock inside the tank, bad pressure regulator or no gas in the fuel tank.

Fuel pumps run constantly, so, over a number of years, they can experience a certain amount of wear — not only in the armature bushings and vanes but also the brushes and commutator. The fuel pump relies on the fuel passing through it for lubrication and cooling. So, any "junk" that’s in the fuel will accelerate wear and shorten the life of the pump.

Dieter Lorentz, a trainer at Bosch’s Broadview, IL, facility, explains that most outright pump failures happen because of some type of fuel contamination such as dirt, rust or hose debris from deteriorating braided fuel lines.

The filter sock on the fuel pump pickup is only there to strain out the big pieces, so smaller pieces of debris can still get through and cause pump problems. Pump failure can also occur if the sock becomes clogged and starves the pump for fuel. With no lubrication, the pump can run hot and self-destruct.

RESIDUAL PRESSURE
Residual pressure is another factor you need to consider when diagnosing fuel pumps. When the pump or engine is shut off, a certain amount of pressure should remain in the system to make starting easier the next time the engine is cranked.

If line pressure drops to zero immediately or soon after the engine is shut off, the engine may experience hot starting problems and have to be cranked longer than normal to restart. Maintaining residual pressure in the system reduces the tendency to vapor lock during hot weather by preventing the hot fuel inside the fuel rail from boiling and forming vapor pockets.

To maintain some residual pressure in the system, most Bosch EFI pumps have a check valve that holds pressure in the supply line when the pump is shut off. The residual pressure specs vary with the application. A typical residual pressure spec for a late-model Audi V6 with a Bosch Motronic EFI system is 32 psi (2.2 bar) after 10 minutes when the engine is cold, or 44 psi (3 bar) after 10 minutes when the engine is warm. By comparison, the specs for a late-model Volvo with a Bosch LH-Jetronic system call for a residual pressure of 27 psi (1.9 bar) after 20 minutes.

If the residual pressure in the line is significantly less than the spec (or zero), it means the check valve is leaking. In most instances, the check valve is part of the pump so the pump has to be replaced if the valve is leaking. But, on some applications, the check valve can be changed without having to replace the pump, so check with your parts supplier to see if a check valve is available separately.

MEASURING UP
Just as important as a pump’s operating pressure is its ability to deliver an adequate volume of fuel to the injectors under all driving conditions. This is especially important on turbocharged engines where fuel needs increase sharply under high boost conditions.

One rule of thumb you can use here is that a good Bosch EFI fuel pump should deliver at least 750 ml (3/4 quart) of fuel in 30 seconds.

Fuel delivery can be checked by first relieving system pressure, then disconnecting the fuel supply line at the fuel rail or fuel distributor and placing the open end of the hose in a measuring cup or graduated cylinder. With the engine off, use jumpers to bypass the pump relay. Energize the pump for the specified period of time (usually 30 to 60 seconds), and measure the volume of fuel delivered.

If the pump delivers the specified volume of fuel, it tells you the pump is probably operating within normal limits, that it is receiving voltage through the relay and wiring, and that there are no obstructions in the fuel pickup sock, fuel supply line or fuel filter. So, if the engine is showing symptoms of running lean and/or fuel pressure is low, the problem is a leaky fuel pressure regulator, not the pump.

If a pump’s output volume and/or pressure is low, the pump motor might be running slow because of internal wear. A typical Bosch roller cell pump should run at 5,000 to 6,000 rpm and pull about 3 to 6 amps. However, as the armature brushes become worn and the brush springs weaken, increased resistance will reduce the pump’s current draw and cause the motor to run slower. Consequently, it pumps less fuel.

One way to check the pump motor is to use an ohmmeter to measure the motor’s internal resistance. As a rule, most pumps should read 2 to 50 ohms if good. If the pump is open (reads infinity) or shows zero resistance (shorted), the motor is bad and the pump needs to be replaced.

Even if the pump motor is OK, fuel delivery problems can be caused by the pump’s voltage supply.

Low battery voltage, low system operating voltage, a poor ground connection or excessive resistance in the pump’s wiring connectors or the relay can all have an adverse effect on the operating speed of the pump. The pump must have normal voltage to run at full speed, so always check the pump’s wiring connectors and voltage supply when you encounter a pump with low pressure or volume output.

The pump’s supply voltage should be within half a volt of normal battery voltage. If low, check the wiring connectors, relay and ground. A good connection should have less than a tenth of a volt drop (ideally no voltage drop) across it. A voltage drop of more than 0.4 volts can create enough resistance to cause a problem.

SCOPING PUMP PROBLEMS
Fuel pumps are sealed assemblies, so you can’t take them apart to see if there’s anything wrong or worn out. But, there is a way to look inside a pump using an oscilloscope to electronically view the pump motor’s performance. By connecting a milliamp current probe to the pump’s voltage supply wire, you can generate a waveform that will reveal a wealth of diagnostic information about the pump’s condition.

A scope will reveal internal wear in the brushes and commutator that may not show up in a traditional pressure or volume test. A pump with a worn motor may still be capable of generating enough pressure to meet static or regulated (vacuum applied) pressure specs, but it may not spin fast enough to maintain adequate pressure or fuel delivery at higher engine speeds or loads when the demand for fuel increases.

Observing the waveform will tell you if the pump’s amp draw is normal for the application, and if the pump speed is normal. Problems such as a bad spot on a commutator or a short or open in the armature will also be obvious in the waveform.

A "good" waveform will generally seesaw back and forth with relative consistency and minimal variation between the highs and lows. A "bad" waveform will show large or irregular drops in the pattern, with large differences between the highs and lows. In other words, the greater the sawtooth in the pattern, the greater the wear in the pump. But don’t expect to see a perfect waveform when installing a new pump. The pattern may appear rougher than normal until the new brushes have had a chance to seat (takes about 100 miles).

The pump’s operating speed can be calculated by counting the number of millisecond divisions to complete one revolution of the motor. Look for the time period it takes the pattern to repeat. Then divide 60 by the total number of milliseconds the pump takes to complete one revolution. This will give you the pump speed in revolutions per minute (rpm).

A lower than normal pump speed and/or a lower than normal amp draw would tell you a roller cell style pump motor is worn and needs to be replaced (assuming, of course, that the pump is receiving normal battery voltage through its supply wire, and that it has a good ground connection).

Jeff Bach, owner of CRT Auto Electronics in Batavia, OH, swears by the scope method for diagnosing fuel pumps. Bach says he has looked at waveforms for hundreds of pumps and finds that, in most cases, a scope will give a more accurate diagnosis than a pressure or volume test — especially in instances where a pump problem may be borderline or intermittent.

Bach says that, since he’s started using a scope to diagnose fuel pumps, he hardly ever uses a pressure gauge. In his opinion, the scope technique is faster, easier, more accurate and leads to fewer comebacks.

On Bosch applications that have a gerotor, rather than roller cell type pump, Bach says a new pump will run at about 4,500 rpm. But, as the pump wears, its speed will actually increase (although the motor’s amp draw will decrease). Problems can start when the pump's speed gets above about 7,000 rpm. He says he's seen some pumps turning as fast as 8,500 rpm.

Such a pump may still be able to meet the minimum pressure specification but won't have enough force to produce much pressure in the return line. This can allow the fuel in the rail to get hot and boil, causing the engine to run lean and contributing to hot start problems.

PUMP R&R
Whether a pump is mounted inside a fuel tank or externally, the inside of the tank should always be inspected and cleaned if you find rust or debris in the pump or filter. Replacing a pump without cleaning a dirty tank will doom the new pump to premature failure.

When replacing an in-tank pump, always disconnect the battery to prevent any unwanted sparks. Then, drain the tank before removing the tank straps and opening the pump’s retaining collar. When installing the new pump, always replace the filter sock and use a new O-ring for the sealing collar.

Finally, avoid the temptation to "test" a new pump by jumping it before it’s installed. Running a pump in a dry condition with no fuel to lubricate it risks damaging it. Also, replace any braided or rubber fuel lines that are flaking or cracked with the correct type of EFI hose.

sammysnakes

i seriously doubt it's vapor lock. gas companies adjust fuel volatility according to the time of the year and temperature in a specific area, so that they can prevent things like vapor lock.

chances are it's the main relay. i had the same problem last summer w/ my EH. all i did was remove it from under the dash, resolder all the solder points and reinstall it. i haven't had any problems since.

riot

I guess I can pull it out and resolder it....

NonovUrbizniz

The opposite used to happen to me in the winter.... the temp drop would drain all the "stored" pressure and if I didn't let the fuel pump prime it would take FOREVER to start... sometimes 3-5 cranks... but if I just leave the car in he "on" position until the fuel pump stops then crank it it starts RIGHT up...

So as far as the vapor lock I think everyone here is wrong... if the gas/tank is heated (by the sun/surrounding) the pressure CAN increase dramatically... this could in effect be messing up the fuel delivery... by over pressurizing the sytem...

If it works fine when you let the pressure out EVERYTIME... then I think it's more a problem with the evap/purge system of the fuel delivery not wiring...

Just my .02.

ill phil

Yeah, I thought by what Nikos was saying that he was completely off on what vapor lock is- Vapor Lock = the heating up fuel causing air bubbles in the A/F mixture, generally from the transfer of excessive engine heat to a fuel line. Since he was talking about pressure, I was assuming that it was just a generalization. But after reading that article I understand what he was saying in relation to fuel pressure, but still don't see heat being enough to boil fuel thats left in the lines or fuel rail. Sorry maybe I'm stubborn. That would mean many of the car that I've gotten tired working on carburated or not and left outside with the hood up in Texas- 100+ Degree weather would have problems like that. I figure if that was the case, Texas would be one of the most common places to see that. Maybe I'm just one of those, don't believe it til I see it hard heads. Hehe. Good article though with lots of info there Nikos!

riot

I hear brent likes it in the poop shoot!

ill phil

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by riot &raquo;</TD></TR><TR><TD CLASS="quote">I hear brent likes it in the poop shoot! </TD></TR></TABLE>


Don't hate cuz I give females vapor-lock y0!

riot

Okay, I ordered that main relay...we'll see if that fixes my problem.

splitime

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by chainsaw &raquo;</TD></TR><TR><TD CLASS="quote">chances are it's the main relay. i had the same problem last summer w/ my EH. all i did was remove it from under the dash, resolder all the solder points and reinstall it. i haven't had any problems since.</TD></TR></TABLE>

Was about to suggest this route, looks like he already ordered a new one though.

riot

Just got the relay. Had a different number on the front as well as a different bracket...but I through it in there and it worked fine. I just swapped brackets and mounted it where it goes. I hope this solved my problem!!

We'll find out today after it sits in the sun for a few hours.

-ryan

slowpokesi

so did it work anus scab?

Daniel_san

I wanna know if it will fix your problem, cause I got the same **** going on