COsborne

I am trying to fix my problems with my car.
I dont have any emissions or idle controls. I have an engine with 1000 miles on it and I have had the hot start problem since Ive owned the car.


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Symptoms:

Starts easily when cold but runs like poo...backfires, etc

Will not start without cutting fuel when hot

Idles at 750 if load is placed on engine but rises to 1200ish if reved

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ECU Test Results:
(Tested with ignition on, engine not running (cold), Battery was apparently low - battery measured at 9.33V)

1G - Neutral Switch - 9.28 In/ 0 Out
1H - Water Temp Switch - 3.34
1I - 5th Gear Switch - 9.41 In/0 Out
1J - Initial Set Coupler - 4.38
1L - Clutch Switch - 0 Released / 9.01 Depressed
1M - Coil With Igniter (trailing) - .76
1N - Crank Angle Sensor G1 -
1O - Mileage Switch - .02
1P - Crank Angle Sensor G2 - .67
1Q - Crank Angle Sensor Ne2 - .67
1R - Knock Control Unit - 3.38
1T - Crank Angle Sensor Ne1 - .67
1U - IGs-T - 4.31
1V - IGT-L - 0
1W - Heat Hazard Sensor - .96
1X - IGT-T - 0
2A - V Ref - 5.0
2B - Pressure Sensor - 2.27
2C - Ground - .03
2D - O2 Sensor - .075
2E - AFM - 4.0
2F - VR - 1.74
2G - TPS - .95
2H - Atmosphere pressure Sensor - 3.9
2I - Water Thermo Senor - 2.66
2J - AFM intake air temp - 2.88
2L - Intake Air temp sensor inlet pipe - 3.9
3C - Injector Rear - 9.27
3D - Fuel Pump Resistor Relay - 9.2
3F - Injector Rear Secondary - 9.22
3H - Injector Front Primary - 9.21
3I - Main Relay - 9.19
3J - Battery - 9.24

COsborne

I tested it with the battery charged and car running...all the 9s became ~13s

pressure sensor was still 2.27 (out of spec) FCD maybe?
IGT-L was.7
IGs-T 2.1
water thermo .33
AFM temp - 2.49
intake pipe temp sensor - 3.84 (out of spec)

5th gear switch was 12V OUT of 5th gear...what with that?

fuel pump resistor - 1.14

injector front primary 12.89

j9fd3s

iTrader: (3)

i would look at your pressure sensor. it should have changed with the engine running. try bypassing the fcd

mike

Scott 89t2

come back when you have 2000-3000 miles. you probably don't have much compressoin yet.

COsborne

pressure sensor doesnt change b/c you are supposed to disconnect the vac line.

This is a problem that I saw with the old engine as well as the new engine.

I noticed that the thermosensor isnt quite in spec, the pressure sensor isnt in spec, The intake air temp sensor is bad (didnt change between measurements ... hot and cold)

My main concern is with the 5th gear switch...my readings are opposite of what the FSM says they should be

Henrik

Fix you intake air temp sensor and read page 4B-83/84 of the FSM - "Hot start assist system" - one of the main inputs is the intake air temp sensor.

Henrik
87TII

PS. The sensor is the same for NA and TIIs.

COsborne

Where is it on the N/A?

HAILERS

1. Your fifth gear switch is not working, or the wiring is disconnected at the switch. In fifth gear the voltage should drop, and rise to approx 12v in other gears(no ground on the circuit). A ground is put on the circuit when in fifth, which puts a ground on the split air solenoid(you have none if the acv is gone).

2. I wouldn't worry about the pressure sensor. That could be maybe the meters calibration perhaps? Anyway it does not seem significant to me.

3. I don't understand the Trail coil not being nearer .8.

4. The intake sensor is located on the throttle inlet . You know, the metal piece the intercooler hose connects to. Two prong sensor. Was the car fully hot? I'll take a look at mine in the morning with a fully hot car(if it ain't snowing). I'd do what Henrix says. I think the cold weather has a lot to do with this odd reading vs the manual. In other words, I don't think its really off.

5. The fuel pump resistor meets the requirements....below 2.0 volts at idle.

6. The battery isn't too sharp seeing those injector numbers with the key just to ON. Seems way low, but then again you could have had the key to on for a long time while looking at the ECU and it went down due to the load.

Although you have no bac.......I've watched the bac voltage. During start it is wide open, voltage is in the low 3-4 volt rangek, then as the car starts it goes to 8-9 somewhere like that. Just saying the bac adds air during the start sequence on a factory original car.

7. Running like poo when cold and backfiring.....how does it act after warming up??? Backfire MIGHT be caused by the lack of a acv. The acv has a antiafterburn valve in it, that opens during sudden deceleration and lets fresh air into the intake manifold to prevent backfire.

8. I don't know what is wrong with the car. I'd do a compression check on each rotor and compare the two.

COsborne

Thanks...I'll replace that intake temp sensor and get back to the ecu again to see what it all looks like. I didnt understand what you said about the 5th gear switch... I mean I understand the principle but the FSM says it should be 12V in 5th where as mine sees 12V out of 5th.... is the FSM wrong or am I just confused?

HAILERS

The intake air sensor(the one on the intake manifold) on my n/a is around 3.4v this morning and its about 35 degrees outside. I think in the summer with higher underhood temps it would be similar to the fsm. EDIT: After sitting and idling for a half hour its dropped to 2.8v, so wait til summer and it'll go down to the fsm.

My lead and trail at 1v and 1x are 6.8 and 6.3. The fsm said approx, so approx it is.

I don't think there's anything wrong with your intake air sensor.

Nice to see a tps set right. 0.95v.

And my pressure sensor is 2.33, engine running and vac hose off.

COsborne

mine ran an hour and I only have the pusher fan on so the engine temp got to where the pusher fan was coming on and going off to keep the engine cool. That should have been plenty hot enough to bring the intake temp to the right temperature

5th gear switch...what do you think?

HAILERS

Don't know what garbage I wrote earlier, but at pin 1I, you should see zero volts until you put it in fifth gear, where you will see 12volts. Selecting fifth puts a ground on the circuit thru the switch.

I just looked at my 87n/a and that's what I see. Zero volts at any time except when in fifth, when I see 12volts. Sorry, can't look at the turbo, but it should be the same.

Sorry about the mistake in the earlier post.

EDIT: I must be doing something wrong (fifth gear sw). I look a the schematic and it makes me think something is wrong here. I'm going to go back and look again later.

HAILERS

Ok. I admit it. I'm lost. The n/a and turbo cars both act *** backwards from each other. ON the n/a if I leave the key off and check ohms on 1I, it shows a ground, which goes away when I put it in fifth. The grounds value varies dramaticaly when flipping from fifth to any gear. Sometimes nine ohms, other times waaaay out there. This explains why I don't get the 3000 rpm start up lately. Kinda suspected it though. Same with the turbos ground. Flakey. I need another switch or find whats wrong with the connections/ground.

n/a....ground in any gear but fifth. But definetly a bad connection to the ground.

turbo.....ground only in fifth (like I think it should be). But the resistance changes quite a bit as I flip in and out of fifth. 9ohms sometimes, others 30ohms. Bad something there.

So both cars have a fifth gear switch problem no matter what. Too cold to fiddle with cars today. Both run great, so I'll fix it some other time.

COsborne

Sanman checked his turbo car and saw the same that I did. 12+ volts out of gear...0 in gear

I dont understand why it would be opposite though...doesnt seem like its wired wrong

someone needs to go check theirs

dr0x

If I didnt just finish putting my ecu back in I would

HAILERS

Before someone jumps my butt.....in one of the above posts I mentioned something about the 3000 rpm start up.......uh, just another mistake. Forget those words.

One thing I do know. The schematic....see the split air solenoid? And how its spliced into the over the top switch? Well that solenoid pulls in when in fifth gear, so I know that in fifth....you should be getting a ground on pin 1L.

So, turn the key off. Put your positive lead on the pin 1L. Put the other lead on a good ground. See if you are getting a ground when you are putting the gear lever in fifth. I say you should get a ground on the meter. Should be just 1-5 ohms, not any more. Out of fifth gear, no ground. That's my story and I'm sticking with it.

COsborne

I talked to Greg Burns about it and he said that since its the opposite of the reading im supposed to get then maybe the wires are hooked up opposite of how theyre supposed to be since my reverse light also does not function. I'll check this out tonight and get back here with my info.

COsborne

I dont mean to clutter this thread but I replaced the intake temp sensor and it still reads 3.93 with the car off... it goes to 3.86 or so with the car idling warm

GRRR!!!! What the hell do I do?!

HAILERS

Wait til summer whent the under the hood temps get higher. That sensor is supposed to read 1-2 volts IF the temp is 176 degrees F. Notice how the reading falls after the engine is warmed up? It's not summer.

Since your getting pretty good at removing/replacing the temp sensor, take it out, connect it to the harness, and put a hair dryer to it. Turn the key on and see the voltage drop.

COsborne

yeah ok that worked but the car still isnt starting hot

HAILERS

It's just a theory.....but if the bac goes full open when the starter is engaged, adding more air to the engine when during start, and your car has no bac...........

HAILERS

Ok. About the fifth gear. You should have 12v in any gear or neutral....except fifth gear where you should see less than 1.5 volts. Thats what the book says and thats the wasy my 87 turboII is.

The N/A model is just the opposite. In fifth gear you should have 12volts and any other time less than 1.5volts. That is indeed the case with my 87N/A

Your car is wrong. I know not why. It seems there are two different fifth gear switches. One for turbo and one for N/A. Working just the opposite.

So, I'd suspect the fifth gear switch in your transmission.

If someone thinks this is wrong, please let me know how. I'm looking at the data from the fsm for turbo and n/a .. I don't think swapping wires will do anything. Just a make/break type switch.

Sanman

Hey guys, I am getting the opposite reading for the 5th switch in my '87 Turbo as well. I still have my 1500 RPM idle. Does anyone have the TSB's (full )? Maybe there's one about a typo in the FSM 5th switch spec for the Turbo cars.

-Cosbourne, I've tried and tested the intake air temp sensor (both of them) and it won't affect your car that way. I'm interested in the 5th switch reading, I think we should focus on that.

Sanman.
'87 Turbo

HAILERS

Sanman........I am really pretty sure the way I described the turboii is correct. One way to prove it is to go to your split air solenoid. That is the rear most solenoid on your acv. It has a two wire plug. Put a meter on the black/white wire. Turn the key to on. You will see 12v. Now put the car in fifth. The voltage will go to less than 2volts. That's because the fifth gear switch, when in fifth, puts a ground on the split air solenoid, causing the voltage to drop from 12v to less than two.

If you have no meter, unscrew the split air solenoid, being careful not to drop the poppet valve and real small spring. Now turn the key to on, and see that the poppet is not pulled into the solenoid. Now put the car in fifth. The poppet is drawn into the solenoid. Because you put a ground on it thru the fifth gear switch.

Yeah. Is there a tsb?????????

Sanman

This is exactly what I found on mine Hailers. I'd say the FSM is wrong. We need someone to post the TSB's in full. Anyone?