kUrb3d

Ok I have two issues I'm trying to figure out...I just completed a mini me swap on my 92 LX and I have two immediate issues...May be related

A little background on symptoms: ...both mechanical and ignition timing are bang on, even after I took the car out...but I did run into a problem after running the car for 15 mins; it was running excellent lots of power and no smoke under load, went through every gear accellerating and decelerating at about 60 percent power ( trying to seat piston rings ). When I slowed the car down and pulled over the idle dropped off the chart and it started to sound like a 2cylinder harley davidson...almost seemed like my car went into safe mode? I shut the car down and let it sit for a couple minutes, started it was fine, two minutes down the road same thing. Got my car back to the house shut it off, checked all the hoses and wiring, all good. Checked the ignition timing again, bang on...Took it around the block once more and it did it again... literally sounds like a Tank...Got the car back home again, and noticed my fan isn't coming on at all, I know the car was def up to temp, a little higher on the normal side than before...I have checked the fan itself, it works when connected to the battery. And when the car gets to temp I can hear a click, a drop in idle but no fan...Tested the fan to battery, works fine, I traced the wiring for the fan back behind the passenger head light, a small relay is sitting there tested with ohm meter( while car was still hot) no continuity( i beleive I should have continuity here if I am right) no continuity when cold, continuity when hot, correct me If I'm wrong... I guess my question is; can this issue with my fan not activating cause my car to go into a get me home safe mode? Please if anyone has any info feel free rip me...My build is posted in my signiture minus the LS throttle body, using stock b7 throttle body and components...please help!

Thanks

Former User

So the Cliffs Notes are that you have two problems -- low idle and radiator fan won't run -- right?

Low idle:
Any CEL codes? If not, try cleaning the IACV, bleeding the cooling system, and replacing the PVC valve (if it is clogged).

Fan:
Bleeding the cooling system may help. If not, unplug the 2P connector for the fan switch located on the thermostat housing and short the two terminals with a jumper wire. Does the fan now run when the key is turned to ON(II)? If so, replace the switch.

kUrb3d

Thanks for the quick reply,

1) I have an intermitent low idle, when I start my car cold it idles fine, even after it warms up it's still fine, but it's when I drive it for a bit it goes haywire...(sounds like it's firing on 2 pistons) with no power...let it sit and it's fine again...

2) I will try jumping the fan switch this morning...I can hear it click when I get to temp but no fan...

No cel codes at all, even when my car goes wonky...


Thanks for the input will test that switch...and try to bleed the cooling a little...

Have you every heard of a car going into some sort of safe mode?

Former User

So it's not a specific idle problem? There's also a loss of power while driving? If so, what condition is the plugs, wires, cap, and rotor?

Does the CEL work? It should turn on and then off after 2 seconds (if there are no codes) when the key is turned to ON(II).

----------------------

Bleeding the cooling system may take 20-30 minutes:

1) Park the car on an inclined driveway with the front end higher than the rear.

2) Push the dash heater lever/**** to MAX heat.

3) Follow the directions in the diagram below (hint: the bleed bolt is located where the upper radiator hose connects to the engine):

kUrb3d

ya cel works 'on' for 2 secs then off when key is turned to 'on'

Ya the car has lots of power and a stable idle until it warms up thoroughly and then it sounds like a shermin tank, let it cool and it's fine for a few minutes...I've got all new plugs, wires and distributor.

Thanks for the bleed procedure!

Former User

Check whether unplugging the O2 sensor eliminates the problem.

kUrb3d

Will do next time it happens...going over to my buddies house right now to test the switch, bleed the cooling, and will take it for a little spin, if it happens again i will disconnect the O2 sensor to see if it stops poor idle...

Thanks again...

Former User

Just to clarify, this is not just a poor idle problem because you also lose power or have poor performance while driving, right?

HiProfile

If you cleaned/changed the IACV or FITV, or cleaned/changed any part from the throttle body to the valves, you should reset your idle:

On obd1 Hondas you warm the car up (fan comes on), disconnect the IACV, move the brass idle screw to get the car idling at 400rpm, turn off, then reset the ecu. You definately need the fan working to get this right.

If it does the same stuff afterwards, you need to check if any codes popped up. To do that you need to find the service connector (above ecu, blue 2 pin plug), and jump if with a paper clip while it's idling like crap. Codes generally are stored for later recovery, but sometimes they won't. I've had issues with dpfi2mpfi2obd1 swaps where the sensor in the distributor is too picky, and idles like *** occationally until you use sheilded wires. At those times it will show a solid CEL, and show a code 4.

kUrb3d

the idle sounds good(no tach) doesn't sound too high or low, there is a little wander in the idle but not a lot. I bled the coolant, and checked the fan switch on the thermosdat, when I jumped it the fan came on. I jumped the service connector to check the ignition timing and it didn't shoot a code...and the ignition timing is spot on. The fan problem could be from before the swap, since jumping the fan switch worked, does that mean my switch is bad or could it be something else with the cooling system?

kUrb3d

I did change IACV but not te FITV, and haven't cleaned either...

When I warm up the car the Fan doesn't come on at all...

kUrb3d

I just took it out for 10 mins didn't drive it hard and it started to happen again: poor idle, loss of power. Jumped the service connector and it gave me a code 20(two long flash's). I also tried disconnecting the O2 sensor and it didn't help anythinng, but it threw a cel for it being unplugged. I also noticed that it doesn't throw a cel when it starts running poorly. If any of this helps

Former User

Does the battery/charge system light ever turn on when driving?

When the engine is running fine, measure voltage across the two battery posts. Then do the same measurement when the engine is running poorly, but try to maintain normal idle speed with the throttle pedal during the test.

kUrb3d

The battery/charge system light never comes on. When I measure voltage between terminals: -idling good = 14.28 steady reading. Then it starts to fluctuate jumping all over as the car begins to idle poorly there is a little fluctuation but generally staying between 12-15, steadies once in a while at 14.28

kUrb3d

Was wondering if I could just bypass the temp switch and run the fan constantly, then take it for a ride and see if it happens again...would this be worth it? Have read that some people wire a manual switch to fan and just turn it on as the car warms up...

Former User

Yes, but do this only temporarily as the fan motor will have a short life if you run it continuously for the long term.

Former User

The ELD is an energy saving device that turns off the alternator when the system electrical load is low. Code 20 indicates a problem in the ELD circuit. I'm wondering whether this malfunction is the root of your problem.

kUrb3d

okay got my tach working...let the car warm up and it rests at 750 varying maybe 20 rpm each way, when it gets to a certain temp(driving for 15 mins) it starts to wander anywere between 700-900 rpm and never rests...but doesn't die either. If I let it sit for 15 mins I can start it and it will be fine for like 2 mins then start the wander...definitly affected by tempurature, I think...I'm going to clean out my IACV and see if it helps...but I also have to figure out the rad fan as well...still not turning on. Also noticed that I'm not getting that cel code anymore, when I jump the service connector, and no cel's at anytime for that matter.

kUrb3d

400RPM? is this right? I thought I set idle at 750 +/- 50 when warm?

Former User

Did you bleed the cooling system?

kUrb3d

Ya I bled the cooling system twice now. I've checked the upper rad hose, hot-coolant flowing, I've checked the rad fan, rad fan relay and switch to battery and are all fine. When temp gauge gets to Normal idle it sits at 750, pull the IACV it drops to 400. And the ignition timing is bang on at this point.

Right now I'm letting my engine cool so I can test the switch.

kUrb3d

Well I think I've got the most of it now...I cleaned Iacv(not overly dirty but a little), swapped back to my old plugs/PCV valve, redid the idle adjustment and rebooted ECU. Seemed to help a lot... have a lot steadier RPM. RonJ@ht, I'm pretty sure that code 20 ELD is still having an impact on my idle(small waver in idle) and I get a larger dip in idle rpm when anything electric is used. And I mean anything, rad fan, headlights, clutch, brakes: All seem to drop my engine rpm's down to 500, it struggles for a sec and comes back to 750 on the nose. Especially after decelerating and coming to a stop. I am currently hunting a vacuum leak, I'm sure I have a small one at least.

Thanks to everyone that helped...RonJ@ht thanks for the pics, the base idle setting and ecu reset procedures were key...

alexsrx7

did you get a miss at all?

Tico Loco

When the engine is cold, the ECU works in close loop, some sensor do not work at this time and the engine works base on the TPS. When the engine reach normal temperture the ECU works in open loop and all sensors work. It look like your engine works fine in close loop, you may have a bad sensor. Some sensor do not bring a CODE until they are completly wrong, like Oxygen Sensor. But even with a wrong Oxygen Sensor it should run Ok because your ECU system is OBD1. With a OBD2 system ( 1996 on ) a bad Oxygen Sensor gives a bigger problem.

Do you try to unplugged the Oxy Sensor as someone already suggested?

Also, you could have a low coil, is not completly burn, but when the coil get hot you may have a weak spark. A low coil gives problems with the engine idle.

Former User

^Correction

Engine cold = open loop (primary O2 sensor readings ignored by ECU)
Engine warm = closed loop (primary O2 sensor readings used by ECU to control air/fuel ratio)