North American Turbocoupe Organization



Engine miss - Tried the usual
Wittsend Offline
Junior Member
#31
OK, I'm back with more test.

First I made a Fuel Pressure gauge. It seems to be accurate. I made it from the gauge of the "low" side of an old R-12 A/C test manifold.

I got 33 PSI at idle.
I got 41 PSI blipping the throttle.
I got 41 PSI with the regulator disconnected.
I couldn't get out on the road to get boost to see where it went.
It heald the 33 PSI for at least 10 minutes. It heald 25 PSI after an hour. The gauge seems sensitive, so some of that drop may be due to temperature change.

I cleared the memory than ran codes:
KOEO
63 TPS low (hum..., I set it to .95 volts)

14 PIP. Question, will one get a 14 simply because the engine isn't running? It doesn't show in KOER.

KOER

23 TPS out of range (Ok, will reset tomorrow).
25 Knock sensor (didn't test, not worried).
34 EGR Not connected (didn't show in previous test when hooked up).
41 Lean. Not sure why?
73 TPS insufficient (addressed already, will reset).
74 Brake test not important.
76 Insufficient VAM (hum..., I tested it and had .20 to 4.60 volts. I couldn't find any "holes").

Ok, seems to run crappy-er by the day.

What's new KOEO:
The addition of the 23 TPS low.
The LOSS of 42 Rich.
The LOSS of 65 didn't go into closed loop

What's new KOER:
The addition of 23 TPS out of range.
The addition of 73 TPS insufficient.
The addition of 76 VAM insufficient.

As I said I'll deal with the TPS.

The VAM has me baffled as it was not an issue in previous test. It looked clean (no holes) and read .20 to 4.60 volts.

The Lean 41, could that be the fuel pressure? 33 PSI idling, 41 on the throttle or with the regulator disconnected.

Again, any help is greatly appreciated. At this point I'm close to giving up.
Tom
'88, 5 Speed, LA-3, Basically stock (EGR removed)
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xcrunnerbd Offline
Posting Freak
#32
The lean 41 is a condition and should be fixed when you address the other codes. Your fp #'s look well to me. Reset your TPs and do you have a spare VAM to test with?
Project 13 sec. / 30mpg in '88 TC 5Speed : 15.91@89mph / 32+ mpg

On The Car: KN cone, 2-stage Gillis@ 15psi wired to fuel switch, Kirban AFPR @ 39psi, Walbro 255 HP FP, 130A 3G Alt., Full 3" Stinger Exhaust incl. cat. no muffler,

Shelf: .48 T3, ported E6, BPV
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bang4thebuck Offline
Senior Member
#33
I had my vam test good before and it was bad. I ran really long wires with alligator clips from the vam to my digital volt meter that I had a passenger hold while we drove around. I got the car to act up and the voltage was literally half of what is was supposed to be. I bought a remanufactured vam and the problem is gone. I tested the vam a bunch of times while the car was parked and it tested good. Real world testing verified it was bad. Also try driving it with the o2 sensor disconnected. If the problem clear up there is a short in the o2 wiring or the o2 is bad.
1987 TC 5 speed. To date: AGP 50 trim T3/T4 .63 stage 2 turbo, Ebay bov, 28psi, 255hp pump, Kirban FPR, Ebay Front mount, Full 3 inch Exhaust, Ported Bob's Log, Megasquirt, 55lb. injectors, boport 1.5 cam, boxed lower control arms, Methanol Kit, Ram HD Clutch, front lowered 1/2 inch and E.T. Streets for the track. Best so far 12.5 at 110.8. still tuning.
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Wittsend Offline
Junior Member
#34
OK, in our last episode... . :-)

I did some more testing today. I finally dug up a scope at work that, well..., works.

First, my previously listed TPS codes were my fault. In all my testing I forgot to plug it back in (not that it made any other difference).

I reset the TPS. Strangely it was set to .94 volts earlier but when I checked again it was at .71 volts. I replaced my DVM battery so that likely was the reason. Anyway, it is at .94 volts now.

I scoped the TPS and the VAM. Both looked clean, smooth, with no dead spots.

The VAM range was .53 volts to 4.88 volts. There was no door flutter at idle. The signal responded accordingly to throttle input.

The TPS range was from the "set" .94 volts to 4.81 volts at WOT.

Now, this is where it got interesting. I pulled the "Spout" on the distributor and the idle cleaned up right a way!!!

I drove the car like this. While it was somewhat down on power (no timing advance I assume) it was significantly more driveable. There was still a bit of stumble at around 2,500 RPM, but nothing bad like before.

Unfortunately as soon as I put the Spout back in it all goes "wiggy" again.

So, I still have the problem of what it wrong??? I assume the plugs, rotor, cap, wires, PIP, TFI must all be good if the car behaves with the Spout removed.

I never got a code for any of the temperature sensors. I have run the EGR connected and dis-connected without change.

The fuel pressure is 33 PSI at idle and 41 PSI when the regulator responds to acceleration.

I assume the TPS and the VAM are acceptable based on the readings above???

What is left, maybe an injector issue that it throwing the O2 sensor crazy? Or a bad O2 sensor? I did swap out with a used O2 with exactly the same results.

While it was nice to have a sense of driveability today I know driving with the Spout disconnected isn't the best thing. However, it did give me a taste of hope.
Tom
'88, 5 Speed, LA-3, Basically stock (EGR removed)
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Bill S. Offline
Senior Member
#35
the spout connector is the signal from the computer to advance the spark. when it's disconnected the car will run with just your base 10* no matter what.

I would be interested to see what happens to your timing when you put the spout back in... Maybe your computer is doing something odd. Maybe a short or stray something or other on the spout wire?

Check your timing at idle with the spout in. If its erratic I'd check the spout wire. Ohm it out, make sure its not shorting or anything.
'88 TC T5
'85 XR7 Roller
Mods on hold pending swap.
Stinger header & mBC on shelf
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Wittsend Offline
Junior Member
#36
I guess I could title this post, "When good news is bad news." As those of you who have stuck with me know, I pulled my injectors as a last resort to my continuing problem.

Well even after 150,000 mile my injector screens are IMACCULATE. The area around the pintle was immaculate. I'll still follow general recommendation for cleaning. I will also build a test jig to compare flow.

I also ohmed out the injectors. They were all 7.2 ohms.

The struggle continues.

Tom
'88, 5 Speed, LA-3, Basically stock (EGR removed)
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Ryan H Offline
Posting Freak
#37
Have you done a basic boost leak test yet? Maybe I missed it because this is a very long thread. It would be wise to add some edited cliffnotes of what you have already attempted and what has not worked to fix the problem into your first post.
'88 TC Smile Walbro 255HP, Stinger FMIC, PIT BOV, Pro 5.0, Kirban, RR cam, FRPP strut tower brace, T3
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Brano Offline
Member
#38
I have similar problem last two years, but only under load, higher than 10PSI boost and above 4000RPM,engine loose power, when I release throttle, engine is running unstable for approximately 1 minute. Now I have new camshaft, TPS, coolant temperature sensor, turbo repass and many other details and much money....
I´m sad now. Can anyone help me?
Gillis, BOV, side pipes, CompCams camsaft, K&N filter http://www.flickr.com/photos/swngr/
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Pete D Offline
Administrator
#39
Quote:Originally posted by Brano:
I have similar problem last two years, but only under load, higher than 10PSI boost and above 4000RPM,engine loose power, when I release throttle, engine is running unstable for approximately 1 minute. Now I have new camshaft, TPS, coolant temperature sensor, turbo repass and many other details and much money....
I´m sad now. Can anyone help me?
Did you use new valve springs? Does it run bad if you exceed 4000 with out boost?
Pete Dunham


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Wittsend Offline
Junior Member
#40
OK, today I made a setup to test my injectors. I used a F-350 fuel pump (Bosch, 95 PSI max). I rigged it up to pump paint thinner through the injector. I tested for a cone like spray pattern, leaking and timed volume.

Results:

1. All four injectors produced a similar cone like pattern.

2. None of the injectors leaked.

3. While tested to no standard, all four injectors (tested individually) were timed for 10 seconds (full on) into a graduated column. All the injector filled to 73-75 ML. Given the variables it is easily within the range of accuracy to say they are very similar in capability.

Once reinstalled the problem persists with the spout in. The problem basically gone (as always) with the spout out.

So, the mystery goes on.
Tom
'88, 5 Speed, LA-3, Basically stock (EGR removed)
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