Danial

Hey, I've working on a d16z6 crx project and I have gotten a bit confused about the MAP sensor. Specifically why I have one on top of the throttle body and it has never been plugged into the car since I owned it.

Car:
1991 crx
d16z6 fully built motor with comp 59300
p28 chipped ecu (eprom chip), basemap tune

I ran the car for about 4 months of daily driving, getting 35+ mpgs despite the basemap tune. Then it developed a tps CEL(#7) and began to have extreme idle issues (aka if I left it under 2k for any extended period of time the car would die and not be able to run)
--the radiator fan also ceased to turn on even as the thermostat reads high temps, but that is a different issue

Is the fact that I haven't been plugged into the MAP on top of the throttle body have anything to do with my issue? I tried to find a MAP sensor I saw mentioned several times, but was unable to locate and unable to find a decent picture of in a 1991 crx.

Issues:

-The engine dies occasionally, even in gear and under load. It will simply stop firing and slow down by the engine while it is off. To combat this on the drive home I would fire the starter with my keys and feather the gas. This seemed to get the car to start back up.
-most of the time the car starts right up, but often after dying it would cough and turn over but not start. Sometimes it has trouble starting, especially in the wet and cold. I just attributed this to the cam and no tune issue.
-

I stopped driving the car and have begun to buy parts and start fixing the car. I am thinking either it is a fuel issue, a tuning/chipping issue, or the same issue with the TPS. Not sure what to think about the MAP.
--There is no smoking at all. No discoloration in the oil. Vtec works great.
--Fuel pump(walbro 255) is audible when I turn to start and I wait for the sound to stop before I start the car.
--Car pulls much harder than I expected it to with just a cam and weight reduction.
--I cleaned out the fitv and iacv with seafoam and throttle body cleaner. Then let them dry and reinstalled.

--ordered parts--
-a fuel pressure gauge. Theres an aftermarket rail on it and a B&M command flow fpr. I want to screw in the gauge and make sure I have the proper fuel pressure at idle and in higher RPMs. Do I need to check the pressure under load on the street as well? Or is just running it in neutral through the RPMs sufficient?
-compression tester. This motor has less than 10,000 miles on it, but I just want to cover my bases.
-quality multimeter to calibrate my tps and diagnose other issues, my $5 harbor freight one has highly suspicious readings sometimes. A new tps is already installed on the car and this hasn't fixed the issues.
-cap and rotor (new plug wires less than 2 Mo old, I have some fresh NGK bkr7e plugs to replace the current ones that are the same type)

Fixing:
--I found a dangling relay in the engine bay by the fan, going to test that and figure out why the fan isnt coming on. First going to wire a hard switch to a fresh relay and install that so that when I sit in traffic I still have a fan.
--I am then going to recalibrate the new tps I installed and see if that fixes my issue
--I may do the Endyne fpr mod, drilling a small relief hole to reduce fuel pressure when idling
--there is a list a mile long in my garage of other small things that I have plans for but Im not going to type that out here just yet haha



Anyone have any insight for me?
1. about the MAP sensor oddity?
2. the idling and stalling issue?

Thanks in advance,
Danial

PS I have done lots of searching. Google. Love that $hit. Lets see what you've got HT

Oh and here is a pic of the car when it had the previous motor build with a t3/t04. 11.5s 1/4 mile. It now has a jdm front bumper and no boost yet

Danial

Anybody at all? I could use some help

I calibrated the TPS
cleaned all the grounds
replaced the cap and rotor

It seems to be running great now....


BUT WHY IS THERE NO MAP SENSOR PLUGGED IN

Im pretty sure that I am running on a basemap crome tune and that Alpha N is NOT being used

claymonthug

you need a new tps

claymonthug

your map sensor is mounted to the fire wall and runs off a vacuum line probably

claymonthug

take a pic of your engine/ intake/ vacuum set up

Danial

I take back what I previously said, there is bucking upon acceleration, and simply not firing is present I can hear from the exhaust

I will go do that right now and post some up in a few minutes.

I just replaced the tps. Went through removing the d-series tps by notching the heads with a dremel. Cut new screws to length, deburred, installed and calibrated tps.

Danial

From left of the bay to the right, I can take better pics of whatever if they aren't clear



tape is just over holes in the intake




please excuse the dirt

TearSDMF89dx

looks like the previous owner did a wire tuck ... check under your intake manifold to see if its hidden under there somewhere it should be a 3 wire plug almost identical to your tps connector

Aesthetic Gains

iTrader: (1)

Post a better picture of the device circled in white.
I believe it's a GM 3 Bar MAP sensor. Maybe it was put on when the vehicle was turbo to be able to boost more than 11 psi.
The MAP that's on the throttle body is just to plug the hole.
If it happens to be a GM 3 Bar, then you need to tune/basemap it for that MAP sensor.

TearSDMF89dx

wow i need to get my eyes checked i didnt even see that there ...if the ecu is not chipped you could just rewire a connector for the throttle body and run the stock one

Canadian_EF

areas of issue.

ORANGE: gas tank VENT should not be hooked up to throttle body. Run the hose to the passenger wheel well, near the orange arrow.
RED: Needs to be capped. simply for emissions (connects to charcoal canister, delete during tuck usually
BLUE: map sensor isn't hooked up? there should be a plug around there, might be plugged into the device that Tonio circled. I didn't read the post till later, it could either be OBD0 firewall mounted purge/map or the GM device. Sorry guys.



PINK: This should go to the crankcase ventilation or PVC or whatever. It's a black box under your intake manifold. The hose runs through a hole near the smaller pink box.

GREEN: This is for your brake booster vacuum line. Although not essential, it should be hooked up green box to green box.


Also it occurred to me that your fuel rail is mounted upside down??? Or backwards or whatever. The fuel pressure regulator should be on the other side I thought, but I'm probably wrong/stupid because I've only really worked on my Y8.

Danial

DING DING DING! Thanks!!
I pulled it out and found that the vacuum hose had been partially tucked into the firewall. The hose was kinked and the MAP wasn't functioning. Regardless, fixed it and car still isn't starting.

It is chipped, I am currently running a crome basemap tune that the PO gave me

Wow so he had alot of vacuum issues here...
(orange) I will fix the gas tank vent, i had no idea that was what that line was for lol

(PINK) Im not sure if you can see in the first picture of the whole bay, but currently the PCV is being drawn into the intake piping before the throttle body, is that wrong? Should it be corrected?
Currently the pink line is what is connected to my brake booster.

(GREEN)
Since the pink vacuum line is going to the brake booster, I suppose this vac line was capped from the turbo setup? Does the location vacuum lines connect make a difference?


Thanks for the help
Dan

Danial

UPDATE:

The car stopped starting. It turns over and you can hear it cough hard, but no start.

I am getting about 50 psi of fuel pressure at my gauge on the fuel filter. I am going to drill the endyne relief hole as soon as my drill bit comes in the mail.

I got some injectors I am going to soak and then rebuild.

I am getting conflicting advice on where to test the spark. Lots of people say arc it to the chassis, but some older autocross guys at my work said I could damage other electrical components

video_voide

if i had to guess, based on my own experience, i'd bet your dizzy is dead...

Hidenplanvew

Thought stock fuel pressure should be 32 to 42 psi.. correct me if i am wrong

Canadian_EF

PCV needs a vacuum on it in order to have positive pressure. With a turbo set-up, that might be different, not sure. I know it causes issues with a stock motor.

It probably doesn't make a difference, but, it makes sense to have it hooked up in the proper location, regarding the brake booster line.

Ground the plug to the block or chassis. Shouldn't make a difference so long as it isn't for a prolonged period of time. It's how I've always checked for spark.

Danial

Yea its getting positive pressure from the intake where it is currently hooked up. I was just wondering if we wanted to bring in the oil vapors and whatnot after the throttle body for some reason. If its fine, i'm just going to leave that vac line where it is

It would definitely be a shorter run from there, i will move it, wonder if my brakes will feel any different. Probably get applied faster

Thanks, I tried it to the block and no spark. Ordered a new bottom half for my distributor, hopefully thats the issue. The cap and rotor, wires, plugs, and starter are all fine. Also I am receiving plenty of fuel.

At least I'll have lots of new parts in my engine bay now....lol

Danial

Ordering as we speak. Do you think one of the ebay OE replacements will work fine? I can get one new, shipped for $85 from a random seller, $100 from a top rated seller, and $120 from autoparts warehouse. Then there is $160 for the A1 cardone dizzy from summit racing, I have had good experience with their axles in the past and was impressed by the quality.

Probably end up with the $85 or $100 one but just looking for advice from people who have already gone through d-series distributors

You are right I believe, but 46-50psi shouldn't keep me from starting. I have a B&M command flow, so I have to loosen it a bit to lower the fuel pressure. Hopefully there isn't an issue with that.

High fuel pressure, especially at idle is a very common problem with any car that has a Walbro 255lph or any improved fuel pump. If I wasn't cheap and poor I would spring on an aeromotive unit, but I am afraid to spend $160 and then find out I will also need $25 of fittings.

video_voide

I bought my replacement distributor locally, from Kragen/Oreilly (merger), that's a CA autoparts store. I paid a lot ($150?) but with it came the lifetime warranty piece of mind, provided I keep the receipt. Perhaps a similar offering is near you.

Also, when you get it be sure to install properly. They are keyed to the camshaft end, meaning they can only be installed one way. Point being: Do not force anything. And disconnect neg. terminal first!

Good luck!!!

And when you get this sorted, get it tuned to that cam asap.

turbohatch96y7

iTrader: (15)

First of all stop throwing random parts at your car. Test first then replace. If you don't hhave a multi meter stop now and go buy one!

Make sure you have 12v going to your distributor. Usually the blk\yellow wire. If you don't have vooltage trace back to your key switch.
Second check your ground on your thermostat. And chasis grounds. Test for continuity from the frame to your motor.
Check your wiring for the map sensor since you found it. There's a 5v signal from the ecu a ground from the ecu and a input from your map sensor to your ecu. 3 wires total make sure they are not broken and in good shape.
I can get you pinouts if you have a meter and are willing to do these test if not keep. Wasting money.

Btw the only thing to go bad in your dizzy is the ignitor and coil. The rest are sensors that rarely fail.

Danial

Thanks, just got my new multimeter in the mail yesterday. I will go and test these ASAP
Where could I get the pinouts? That would be very helpful

I got a good deal on an new distributor from a friend, but I think I may rebuild the current one and sell it or keep it as a backup as I do beat on the car. Where is a good place to get the ignitor and coil if you have done it before or just any parts store?

turbohatch96y7

iTrader: (15)

Google has the pinouts
Google katman and obd1 ecu pinouts they'll pop up.

Canadian_EF

phearable.net tech section will become your best friend

Danial

Thanks guys, all the info has really been helping me a lot.

I got the distributor today in the mail. A brand new unit. Installed it. Car started and runs. It drives fine. Idle sounds better than before.

NONE OF MY GAUGES NOW WORK.... except for the speedo, but I think thats because it is mechanically tied into the transmission. When I start the car the battery light is illuminated but then nothing else moves or functions.

I'm pretty bummed. They all functioned and lit up perfectly before I changed the distributor.

Plan of Attack
-Check rpm pin on dizzy
-check wiring to cluster from ecu
-go to a shop. I'm thinking Absolute Pro Performance, anyone else in MD have an opinion?