[Long] Timing or ECU problem?

[gt2847c]

Sorry for the length, but I wanted to include as much detail as possible…

1990 Eagle Talon 2.0 DOHC Turbo FWD (stock everything)

I am currently having difficulty with the engine that I have not yet been able to diagnose. I have, over the past week or so, been reading extensively on the VFAQ, Club DSM, 1000AAQ, etc, but I have not seen anything closely related this problem (hope I didn’t miss a search term). I have some assumptions that I will continue to chase down, but if anyone has any suggestions, I'm starting to run out of things I know to check…

History:
I was driving kids to school when I had a heater hose blow on me (read tame driving). I parked the car before the temp needle rose more than a tiny bit, so I don't think there was any overheating of the engine (also it was still losing lots of coolant when I shut it off). It was due for a timing belt/balancer belt change, so I towed it to a garage I have used before. The following items were replaced:

Heater Hoses
Bypass Hose
Water Pump
Timing Belt
Balance Shaft Belt
Bearing Kit for Tensioner/Idler Pulleys
Cam Seals
Crank Seal

When I got the car back, it was noticeably vibrating at idle and got much worse when I tried to drive it off the lot. I took it right back and had the mechanic check it again. He replaced the bearings in the tensioner and idler pulleys and then returned the vehicle to me. Vibration was still bad, and the car had no power, no boost. Just to make sure there wasn't a cylinder problem, I checked the compression in all four cylinders (~150psi) and the vacuum (~19inHg), so that looked ok. This went back and forth a couple of times, but eventually he found that the balance shaft was out of timing, so once that was corrected, the car ran (obviously) much better. During the episode with the vibrations and somewhat thereafter, I noticed that the boost gauge would jump from -7 to 0+ rather than move smoothly as it had in the past when I accelerated. I didn't think much of it at the time, still not sure if it matters or not.

Problem:
Within around 150 miles after the last time the mechanic had the car, I put a full load of fuel in. Shortly thereafter, I started getting sputtering, missing, no power, no boost, and pings/knocks. Other things I noticed were the tachometer was jumping up and down +/- 300 RPM and the idle was erratic (stalled so often that I had to use the hand brake and keep my foot on the gas to prevent it). I checked the plugs to see if I had a bad cylinder, but there was no plug fouling. I figured after all the rain we've had of late, that I got some bad fuel. I drained the tank, replaced the fuel filter, filled it up with 93 Octane and put in some water remover. This didn't make any notable difference. I then pulled out the timing light and took a look (probably should have done this first, oh well). The timing at idle was advanced way off the scale. According to the shop manual, it should be about 8* BTDC. It was about an inch or more below the last mark on the scale (10*). I adjusted the crankshaft angle sensor to the left (retard) as far as it will go. This got the timing back down to about 8-9* and the idle was much smoother and maintained about 750. It runs much better than it did when it was pinging, but it’s not boosting and is very under powered (probably normal for a four cylinder w/o a turbo, but I haven't driven one of those for years). I also am unable hear the "birdie" noises from the turbo during acceleration at all. Doesn't sound like its spinning up. I've parked it for the time being and using (God help me) the minivan for a backup.

It seems strange that it should just jump this far out of spec on the timing; especially given I’ve not had to adjust the time previously. I've checked the cables all around where the heater hoses were replaced to see if anything was obviously knocked loose and found nothing.

Car Specs:
~174000 miles
Stock factory engine- no mods other than TSBs (my father bought it new).
ECU repaired/replaced due to cap failure - no programming changes I'm aware of
NGK OEM plugs (less than 5k miles)
Bosch wires in reasonable shape will probably replace them next time I pull plugs
New timing belt
New balance shaft belt
Replacement bearings for timing tensioner/idler pulleys
New water pump
New heater hoses

Known problems:
Minor leak around exhaust manifold - makes a bit of noise and has a bit of exhaust smell under the hood, but hasn't been enough for me to want to replace the gasket yet. This pre-existed the current problem.

Things I plan to check yet:
O2 sensor voltage
ECU error numbers (no check engine light so far)
Pull the ECU to check for cap damage and will probably go ahead and replace them while it’s out

Anybody have any thoughts? Thx

[MacGSX]

So the mechanic had the car that far out of time? That is a major issue! As for the shaking, I may be wrong but I believe (BELIEVE) The balance shafts have to be lined up a certain way as in a time them selves, but I'm not exactly sure(I just removed mine)

Jordan

[gt2847c]

I don't believe the timing was off when the mechanic finally got the balance shaft back to where it should be. The car seemed to run ok for about 150 miles after the balance shaft problem was corrected. I'm uncertain if the problem is related to the balance shaft problem or not, so I included the details in case it was.

I'm still a noobie with my DSM, I've only ever done the basic maintenance myself. Since I found this web site and all the related resource info, I've kinda wanted to play with my car, but was worried about messing up my primary ride. I figured that this was the last time I'd have a mechanic do the timing belt, but now I wish I'd gone ahead and done it myself anyway.

[flyineagletsi]

Other things I noticed were the tachometer was jumping up and down +/- 300 RPM and the idle was erratic


I could be way off on this but check your battery and altinator connections and make sure they are tight. My tach went nuts when my battery cable got loose. I also had no power and it was all that I could do to keep it running enough to get off the highway (sounds similar to your situation). Your mechanic probably disconnected the battery as a good mechanic should while doing repairs. Personally I would find a new mechanic. Although doubtful that this helped at all, good luck.

[gt2847c]

I know the battery connections are ok, as I removed the battery to swap out the fuel filter. I made sure the connections were tight when I put it back. I'll verify the alternator connection and voltage just to be sure. Though, given the number of stop/starts I had in the 150 miles, I figure if the alternator was giving me problems, I'd have noticed it having starting problems.

[gt2847c]

Sorry for the delay on the rest of the test results, but they were due to having to run my oldest to the hospital and doctor a few times.

To flyingeagletsi: I checked the voltage from the alternator and its running around 14 volts, so that’s OK. Thanks for the suggestion.

BTW, the original heater hose break sprayed coolant all over the rear passenger side quadrant of the engine compartment. The connectors on the firewall and the throttle body were quite wet from this spray. Don’t know if that might have caused any issues.

I ran through the “Simple DSM testing procedures” document and here’s what I found so far:
ISC: Checked the resistance between the pins and all the pairs showed around 33 Ohms, so this looks OK. One item of note, when the engine was around idling and when I shut it off, I heard a “skritch” noise. Not sure if that’s normal or the ISC or throttle plate is sticky. Suggestions?

O2 Sensor: I checked the resistance on the o2 sensor heater coil and got 13 ohms, which was close to the expected value, so the heater coil looks OK. For the sensor output itself, I believe I found the correct test port on the passenger side (the only single wire connector I could locate). It appears that there was no voltage on the test port, so the O2 sensor may be dead (although the ECU shows no code). I ran the engine long enough to get the temp up to normal operating levels, so I expect that I should have had some reading on it. Going to go ahead and replace this.

Intake Air Temp: I checked the resistance across pins 6 & 8 and got nothing. According to the notes, this should be somewhere around 2.7 Ohms. I’m going to assume that it is dead. The only replacement part I was able to locate is the Mass Air Flow Sensor assembly which is around $275. Anyone have any alternate ideas on this before I spend money?

Are there any tests for the CAS? I haven’t been able to locate any in the FAQs. The “Simple DSM testing procedures” author mentions that they were unable to find one. I have had a similar lack of success finding anything.

Still trying to find a good picture for the location of the knock sensor to check on that.

[gt2847c]

Finally figured out my problem:





I ended up having to redo the timing belt myself... The mechanic that did the original timing belt work screwed up and didn't pretension the timing belt correctly. The auto tensioner was unable to take up enough slack and the belt slipped quite a bit... Needless to say, I've since fired that mechanic..


The folks over on GA DSM site helped immensely...

[gt2847c]

BTW, for the full thread.... http://gadsm.org/showthread.php?t=36053

[piggylover1985]

Wow the timming mark on the crank is way off huh ? You should do a complaint to the garage that did the work.