I cant figure this out

Topic: I cant figure this out (Read 3263 times) previous topic - next topic

I cant figure this out

July 11, 2012, 08:57:41 PM

My car runs fine when it wants to. It's an 88 2.3t 5 speed. About 3-4 weeks ago, It sat for about 3 days after 3 months of non stop driving. After it sat for a couple days, I decided to take it out for a spin. I got in and filled the tank up at the local corner store. Drove about 15 miles and it started running a little rough. Like if the fuel filter was dirty which was the first thing that came to mind. I also assumed that the gas station that I stopped at had dirty fuel, judging by the way it looked (ugly looking place). So I didn't think much of it.

It has progressively gotten worse since then. I changed the fuel pump strainer, cleaned the injectors, changed the fuel filter. The plugs were changed about a month ago and only have about 300 miles on them. Fresh oil and filter last week. I have a code reader and it gave me 23 and 66. 66 is the VAF, so I grabbed the one I have from the other TC (same year and everything) swapped it and it still runs bad. And get this, yesterday I tried showing my dad the problem, so we got in and took it out and the stupid thing drove excellent

. We even decided to go to the home depot about 12 miles away. Code 23 refers to the TPS. I dont think that may be the problem, but I'll get a new one and see. Could it be the cat converter?

Any thoughts on what the hell is happening with this car?

I cant figure this out

Reply #1 – July 11, 2012, 09:03:21 PM

Well, cat won't be intermittent. I'd rule that out. TPS is a definite possibility. If you have an buttstuffog multimeter you can watch the response. Digital doesn't really work for this.

Here's my understanding of what might happen with a bad TPS or VAM signal:

LOS (limited operating system or "limp home")

Should a serious fault occur in the EEC IV system, 2 forms of LOS can be called upon:

1. In the event of a serious fault, all sensor signals are ignored and fixed values are applied. The ignition timing is fixed at all engine speeds. A basic injection setting is applied providing a constant volume of fuel for the limited engine speed and load still available. The fuel pump constantly runs with the ignition switched on.

2. When an individual sensor fails, the sensor is allocated a fixed value corresponding to a warm engine characteristics. Cold starting and warm up are likely to be affected when the LOS is in this form.

I cant figure this out

Reply #2 – July 12, 2012, 12:20:18 AM

Flylear45 does have a very valid point. It is probably kicking into limp(LOS) mode. This is what I would do. first I think about how the VAM and TPS work they work together as a team. Since you are getting codes for those two pieces I would start testing them both. Look up how to test the TPs like flylear45 said need to use and OLD STYLE with a needle that moves not a digital one. Easy to see the needle drop down with intermittent faults than with the flipping random digi read out. Find the correct wires to test for the TPS and very slowly work the throttle and watch the needle on multi meter to see if it drops anytime while slowly going from closed to open and back to close and I mean VERY SLOW rotation. Then also check the base TPS setting. it should be .94-.97volts throttle closed and work up to almost 5volts when fully open. Then once all of that checks out move onto the VAM and find and test that in the same manner. Just think of this the Vam tells the ECU this and TPS tell it that but it uses both of those to kinda get better guess at what is really going on with the motor. So if the Base Vam/Tps settings are off it thinks your giving it gas or this much air is coming in. So then it thinks well then we need to give it/take out this much timing/ open close injectors this much more/less. I know its not like party time doin this stuff but gotta do what you gotta do and make sure you check for loose/bad connections give them a nice wiggle while they are hooked up and you reading the volts/resistance.

Hope that helps
Stuckman

I cant figure this out

Reply #3 – July 13, 2012, 12:42:56 PM

Thanks guys, I'll check that out when it stops raining. It's been raining for the past week, and is expected to rain thru next Thursday. Rain > Heat

I cant figure this out

Reply #4 – July 20, 2012, 11:20:37 AM

So I changed the tps, adjusted and it's where it needs to be. .97 at idle, 5.10 at full throttle. But now the car runs like shiznit for about a mile and a half (no throttle response, sound like its not getting enough air) and then it runs great. But if I leave it sitting for about 30min it does it again.

I cant figure this out

Reply #5 – July 20, 2012, 12:22:21 PM

Have you run codes also did you clear/reset the ecu before you installed and tried the new TPS? I would also say it kinda sounds like your O2 sensor heater may have gone bad. Run it for a mile and half and it gets heated up to operating temp, then things run great. Then when it sit for 30min or more the O2 sensor has cooled back down, maybe not fully but sure it not up to operating temp. O2 sensor part might be fine prob just the heater portion not working. With the info at hand that is the best I got for ya

Hope this helps
Stuckman

I cant figure this out

Reply #6 – July 20, 2012, 05:40:02 PM

Not that I have any suggestions other than the O2's as previously mentioned, the whole as close to 0.99V with the TB closed is a myth with the EEC IV's. Read here:

http://www.my5oh.com/forum/viewtopic.php?p=144

Joel is one guy that has the EEC IV programming figured out.

Darren

I cant figure this out

Reply #7 – July 20, 2012, 08:46:46 PM

The problem was my VAF. I swapped it and it's running great.
Thanks to all you guys and your experience. :bowdown:

I cant figure this out

Reply #8 – July 21, 2012, 07:23:59 AM

Hoorah!

I cant figure this out

Reply #9 – July 24, 2012, 12:23:10 PM

I was wrong it went away that day, but came back.

I drove it about 100 miles on sunday, and the rpm would get stuck at 2000rpm (after it was driving fine). I had to accelerate to get it back down. I checked for codes and these came up, 23, 34, and 77.

I cant figure this out

Reply #10 – July 24, 2012, 02:17:58 PM

I'd check your fuel pump or injectors, something might have gotten stuck in there. Something like what you are describing was happening to my car, it would bog down and wouldnt go past 2k rpm, ended up being the hose for the fuel line from the fuel pump had a little crack in it.

I cant figure this out

Reply #11 – July 24, 2012, 10:22:51 PM

What I meant was the engine is reving at a high RPM. I replaced the little Idle air control gasket, and it now drives fine but the idle is way too high. The engine is at 2000-3500 rpm. There is no way to adjust it, since the screw on the throttle plate is all the way down. The idle air control sensor might be bad.

-The car starts and idles fine.
-Once I accelerate the engine stays reved up.

I cant figure this out

Reply #12 – July 25, 2012, 11:09:54 AM

Not sure if you have this page saved or not but here are the codes and how to trouble shoo them for your EEC:

http://www.tbirdheritage.com/turbocoupe/articles/EEC-Diagnostic-Chart.php

Darren

I cant figure this out

Reply #13 – October 10, 2012, 10:21:31 AM

The problem is the distributor. I bought a refurbished one from autozone. The one with a new module. I swapped it out, but now the engine sputters at 500rpm, and slowly works its way up to 1000rpm. It takes about 5min to reach 1000rpm. It drives, but feels like a 2.3 n/a. The turbo is spinning very fast. And reaches 18 psi on the guage at around 2500rpm. But I can't feel it.

With the old one it starts and revs great, like nothing is wrong. But it bogs down under acceleration.

I installed another distributor from my non running 88tc, and it does the same thing as with the new dist.

I made sure that each dist. was in the same position as the last.

Why does it run differently with the old distributor, then with the new one? Is the timing off?

I cant figure this out

Reply #14 – October 10, 2012, 10:17:14 PM

You siad its boosting but your not feeling it right? Have you done any work to it before this started? If your timing is on then you may have the issue I had. I just went thru a similar issue where the car felt like a N/A 2.3 but the boost gauge was reading what I had my Gillis set for. Swapped out a bunch of parts with known good pieces I had here, full tune up, checked fuel pressure, checked for boost leaks more times than I could count, ect... Thought I fixed it more times than I could count to, just for it to come back agian the next time. Did some reading on nato and turboford and discovered that if your knock sensor is detecting knock whether it be real or a false sound(or just a bad sensor) that your timing will retard. Im still trying to determine what is wrong either the sensor or a false knock because I listen very carefully for detonation, but try unplugging your sensor for a quick run and see what happens. Id turn your boost down to below 15psi just to be safe since you would be running without it. If it drives like it normally should youve tracked down a area to concentrate on.