Gunner882332

So I just decided to join thirdgen tonight. I have spent many hours looking through threads on here and can not seem to find what I am looking for. Quick backstory on the car. I have an 85 2.8 that my dad recently gave to me. He purchase the car in 2005 from the original owner who had let it sit forever driving it occasionally. My dad drive it regularly for the first year and then did the same. The car has 50k miles on it and he gave it to me last July befoe I parked it for the winter it started leaking a lot of oil from the valve covers. The check engine light was also on but has been since my dad bought the car. I took it out this summer and flashed the codes and got a good ol code 34 (maf). I am bringing. Both my issues up wondering if they may be related. Changed the egr valve (realized old one was broken) maf,ecm, and checked signal and supply to the sensor and everything checks out. Now once I got the valve covers done I drove it for 3 days and ran great. Morning 4 started it and ran like garbage and the check engine light was gone. I knew the original owner before my dad bought it and I have never seen the check engine light off or it run this bad. I drive it to work running badly. Got off work started it up, check engine light on, running great. The next morning went out and wouldn't start. The following weekend I started checking the basics and realized the plugs were oil fouled, all 6 of them. Cleaned them off, drove it to work yesterday, check engine light on, running great. After work check engine light off, running like garbage. I pulled the plugs today and they are oil fouled again. Like I said I have searched the threads since this first happened and found the basics. I know everyone will say leakdown test compression test bad valve stem seals but it is doing it on all cylinders and never has done this before until 4 days after I did the valve covers. Like I said I am new to thirdgen and i apologies in advance if I put this in the wrong area or anything like that but any help or input would be appreciated.

drdave88

iTrader: (3)

- You kind of answered your own question, start with a compression test and see where you are at on each cylinder.
- The oil on the plugs and running like crap intermittently may or may not be related too.
- Why did you replace the ECM? Just throwing parts, hoping to shut the check engine light off or was there a reason?
- Also, can you better define "ran like garbage"? Misfire, stumble at idle, all through the RPM band, loss of power, etc?
Where are you at with a tune up? Gotta have a good baseline before you can really diagnose anything. Read this: https://www.thirdgen.org/forums/v6/6...or-tuneup.html

Gunner882332

I would like to start by saying thank you for the reply and I have the answer to your questions below.


- The oil on the plugs and running like crap intermittently may or may not be related too. - I understand this may not be related but every time it runs good, ever since i first laid eyes on this car 20 years ago, the check engine light has been on. Every time it runs bad, the check engine light is off, I pull the plugs and they are severely oil fouled and this did not start happening until after i did the valve cover gaskets.

- Why did you replace the ECM? Just throwing parts, hoping to shut the check engine light off or was there a reason? - The code has always been a 34 (MAF). My dad had replaced the sensor and no joy. He took it to a shop that told him it was the ECM. He decided not to replace it because although the light was on, there were no noticeable symptoms. I pulled the ECM and saw a burn spot on the board. Without knowing or being able to narrow down what that part of the board controlled, i just replaced it.
- Also, can you better define "ran like garbage"? Misfire, stumble at idle, all through the RPM band, loss of power, etc? - All of the above? As long as the check engine light is off and only when it is off, the car will either not start, or start and idle very rough. It will smoke, misfire, sometimes it will idle at low rmp's sometimes it won't idle. When it does run there is a severe power loss. I have to ever rev while releasing the clutch. I guess the beast way to explain it is it runs as bad as it possibly could but while still running. But if I go to start it and it starts easy and the check engine light is on, runs like a dream. I know it sounds crazy but although the problem is intermittent, everything within the conditions are very consistent.

I have not done much as far as a tune up goes. With clean and dry plugs I checked for spark and it looks good. I know that a full tuneup would not hurt but I have 2 problems with this. Problem #1 is that everything you would replace while doing a tuneup is the exact same as it was before I did the valve cover gaskets. I know it still could be a tuneup but I am more inclined to believe it had something to do with the work I did to it I just can not figure out what. Problem number 2 is i do not want to sink much money into this engine. Time is not an issue I can put as many hours into it as needed. If i were able to figure out what was causing the issue and prove it out I would have no problem buying what is needed. I just feel it would be more cost effective to do a 3.4 or a SCB swap rather than sink a bunch of money into a 2.8 for this and that that may not solve the issue without proving it out first. I will try to get a compression test done by the end of the weekend. To do the valve covers I had to remove the egr system, upper plenum, fuel rail/injectors, lower plenum and valve covers. Is there anything you can think of that I could have reassembled wrong that will give these symptoms? I really appreciate the feedback and I home I am making sense.

drdave88

iTrader: (3)

- Did you do the MAF and ECM when you did the valve cover gaskets?
- Where did you get the MAF and ECM? New, reman, used? Was the light off those first few days off when it ran well or still on?
- Valve cover gaskets are not going to cause this kind of issue, unless something else got damaged during disassembly/resassembly. That said, there isn't much to pull when doing VC gaskets, what all did you remove? Anything more than the upper intake, fuel rail, and some brackets (trying to remember all of it from years ago when I last did one)?

Gunner882332

The MAF was done prior to VCG and ECM after the first time it started running bad. I got the MAF from Autozone and the ECM off Amazon. As far as parts removed, in order to get the calve covers off I removed the EGR, Vac regulator valve and Vac switch (just removed the mount they were all on but kept it assembled), the upper plenum, fuel rail and injectors, lower plenum and then VC’s. I will also put a condensed timeline below. This is everything that has been done to the car since the day I got it.
July 2016 – Visited my dad in WA state where he gave me the car (check engine light on), drove it 2000 miles to Iowa where a live without missing a beat.
When I got home I pulled the codes and got code 34, I pinned out MAF plug and things check out so I replaced MAF sensor, check engine light still on.
Drove all summer with the check engine light on, ran good but would sometimes die at idle
October 2016 noticed a decent leak coming from the valve covers, parked it in my garage for the winter.
April I started to do the valve covers and also realized that the EGR valve was broke so I replaced it
Earlier this month I finished (I travel during the week for work) The car fired right up, idled great and ran good. I would go out and start it, let it run and shut it off just to see how it ran (check engine light still on)
Drove it on 6/11 and ran fine, clean idle clean rpms check engine light on
Same results on 6/12 6/13
6/14 started rough, ran horrible on the way to work, check engine light off made it to work. After work went to go home, started great ran great check engine light on.
6/15 would not start
6/17 checked for spark realized plugs were severely oil fouled, cleaned plugs, put back in started and ran great check engine light on
6/18 drove around town no issues check engine light on.
6/19 started up great ran good check engine light on. After work rough start, no check engine light, ran horrible. I then joined the site and made the original post last night.

After I replied to you this morning I got a little input from my brother. I pulled the plugs and cleaned them, started the car (check engine light off rough idle) and pulled the pcv valve. There was good vacuum going into the valve. He was thinking that maybe there is too much pressure in the crank case that may have caused the valve covers to leak to begin with but the pcv valve appeared to be functioning. Any thoughts on this?

Once again, thank you for your input.

drdave88

iTrader: (3)

Do you still have the old ECM? Maybe try swapping that back in if you do, see if the issue goes away. Was it a reman ECM or used? Coming from Amazon, there's no telling what you got really. Part numbers match right?
Does the valve rattle when you shake it? That's a quick way to test those. It there's no noise, replace it. That's not going to cause your intermittent issue though.
Aftermarket MAFs aren't well known to do well either, it's pretty well documented on here. The Delco ones are usually the best replacement. Not saying that is for sure the issue either, but just throwing that out there as a possibility.