Hi guys,

Im completely at a loss here about what is going on. Car has just always started and ran with no problems. I was out with it the other day, all good - came home and parked it in the carport.
Go out to start it today and it starts right up, but will not run at all! I can do it over and over. I have to keep going on and off the throttle to somewhat keep it running. If I keep a steady throttle it dies - and if I let go it dies..

See video:
No SES light (yes it works).

Anyone have any clue where to start looking?

Thanks!


Ken

 

I'd check fuel pressure and get a datalog.

 

Hi, thanks for your suggestion, sorry for the late reply!

Fuel pressure is nice and steady right around 40.
Finally got a cable to connect for datalog, but Im not reading out hardly anything, but then again I’ve barely touched winaldl before.

All I get is this?



Anyone have any input what Im doing wrong?

Thanks!


Ken

 

Nevermind, I found an error in the cable so now I got connected OK.

Would anyone care to take a look at the log files and see if anything makes sense ?

Thanks a million! Been in the paintshop half the summer, then I was away, and the last 3 weeks or so it has been down because of this - so it would be fun to get a few more days with it before the weather turns bad and it goes into storage ..


Ken

 

Nice work getting those logs. Looks like you threw a Code 44, which could be a lot of things but it's somewhere to start. Try checking some of these things:

https://www.thirdgen.org/forums/tpi/...ml#post2157371

Your fuel pressure should be good, I would also get an ohm reading of all the injectors and see where they're at.

I have also uploaded your longer datalog as a comma delimited csv so it's easier for others to read without conversion.

 

Thanks man!
I am not sure if the code 44 is slightly misleading, because out of all the times I've started it, it has thrown a code once, and that was the 44 yesterday when I tried to let i idle on its own and it was idling very low and bare chugging along before it died. The 44 came right before it stopped.
I will ohm the injectors next to see how they are.

Thanks again!


Ken

 

As I recall, the last time it was running a bit rough the #4 exhaust valve was bent:




It can't be the injectors - They were just cleaned 19 years ago:

 

Heey man! Great hearing from you!

Yeah, and you know what, that car has started and pretty much ran perfectly for all those 19 years since you got her running So I guess it is acceptable if it needs some attention now I did have it apart couple of years ago replacing all gaskets, but that's about all that has been done to the engine.
Cant't believe you still had the pics

Haven't been able to check the injectors yet, will try to get started on it today!



Ken

 

Was the engine running when the fuel pressure was tested at 40 PSI? If not, it may be worthwhile to verify consistent running fuel pressure,

In reviewing the video clip, it might be good to verify the IAC is clean and functioning. If the WIN ALDL can be set up to monitor the IAC counts that may be a hint about its operation. The data stream shows a constant 145 for IAC, which doesn't seem correct given the RPM variation.

Has the EGR been disabled (temporarily) for diagnosis? The EGR pulse rate seems to be inconsistent in the one large scan data stream. Disabling the EGR might be helpful it is creating a large vacuum leak. The same applies to the brake booster, and the PCV.

 

I'm i reading this correctly? The injectors were cleaned 19 years ago????? Is that a typo?

 

I ohmed the 6 injectors I could get disconnected without loosening the runners. They alle were in the 16.4-16.7 range.

No, the engine was not running when checking the FP at 40, I did now, however, and it is steady at 43’ish while running.
I pulled the TB and the IAC and it actually looked pretty decent as far as I could see.
So, I put it back together, added a bottle of injector cleaner and now it actually runs pretty decent.
Will see if I can figure out how to monitor the IAC counts. I have not done anything to disable the EGR to my knowledge.
Will try to run another scan now that it runs decent, and post it.

Southbay08,
Pretty much Well, to be fair, they were actually replaced, not just cleaned - but yes, that was back in 2002 - has run ever since
You reckon it’s time again?


Ken

 

probably wouldn't be a bad idea...

 

Technically, they were cleaned and flow-matched by rotating other stock injectors into the set. Half of injectors in the eventual set were the original RP injectors removed from the car. Obviously, the solenoids in those lasted a lot longer than Multecs. This was the injector chart:



It couldn't hurt to check them again, but the result of a streamer or dead unit wouldn't likely be the surging shown in the video. A stuck injector might do a little of that, however, A power balance test should reveal that.

As for the EGR, simply removing and capping the vacuum supply to the ERG solenoid should remove that as a question (for now).

 

SouthBay,
Sent you guys a message on your site yesterday or the day before for a recommendation and a quote for a set

Vader,
There goes to show you to not trust my 19 year old memory You are of course right, I thought we went to get some new ones, but that may have been a new set of rockers.
I tried capping the vaccuum supply to the EGR, no difference. How would I go about to do a power balance test ?

Today when I started it, it was pretty much as bad as before. Seems to get slightly better and able to somewhat keep an idle on its own when warming up a bit. I hear it poppin' quite a bit in the exhaust, probably from unburned fuel?
Attached is a new scan from today, not sure if it contains two runs or just the last one. However, the last one it idled bit on its own first, then was about to die so had to give it some throttle and then it would loop the rpms when holding a steady throttle.

One thing I noticed that Im sure is totally unrelated, I just became aware of it, is that my tach is way off? When WinALDL shows around 1800-2200rpm, the tach shows 4000-4500, when nearly surging WinALDL shows 750-800 which sounds about right, while tach shows 12-1400 rpms.

And here is a short video of parts of the last scan and how it sounds at higher rpms and when surging, and right at the end before it dies is when it throws the code 44:

Thanks again for your input guys!


Ken

 

Hey Ken,
sorry did not receive the message... however i just responded to the private message you sent today.
In process of building a new website. I've received a few complaints about not responding to messages however i never receive them.
Sorry bout that

 

Oh, okay no problem - that happens.
I didn't send you a PM though (nor get one from you) , but will do


Ken

 

You got a set of Crane roller-tip rockers. The injectors were cleaned/matched in Michigan, then sent back to me.

The injector power balance test requires the engine to at least be running at a reasonably stable rate. https://www.thirdgen.org/forums/tpi/...ml#post2221387

 

That's right - I knew you'd remember

Oh okay - will try to get it back to the somewhat stable way it was running a couple of days ago and give this a shot. Thanks for the link to your explanation!


Ken

 

my pleasure....keep us posted

 

Sooo, I just had my brother assist me and got the car running (rough) until warmed up, stopped it briefly. Then when starting up again it still ran rough, but stable enough with a consistant throttle to be able to disconnect the injectors one at the time. Turns out that for 2 of the 6 we disconnected it made no difference!

So i guess we can conclude that its time for to replace the injectors - agree?

Thanks!


Ken

 

That seems pretty reasonable. It's almost as expensive to clean/match them as replacements any more.

 

Thanks, Vader!

Yes, and Im not sure who even does that over here.


Ken

 

I'm betting it you crossed the Baltic into Wilhelmshaven or Kiel you could find a place, but it is so inexpensive to replace them that it might not be economical.

Injectors have transitioned from a rarity when our cars were new to a commodity item now. On the other hand, try finding a set of points and/or condenser today. A non-Chinese uniset for a '71 Chevelle is almost $50, and a single injector can be had for under $30 now.

 

Yeah probably so, but I actually found a place here in Norway today that could do it. However, at $450 for cleaning and testing, it makes no sense other than to save time. So, I'll be ordering a set from over there instead


Ken

 

$450 for cleaning and testing your injectors?????? Damn I'm doing something wrong....

 

Yeah 😂😂
Did you see my PM?


Ken

 

no i did not? I'm supposed to receive emails with all notifications from members....Let me take a look.

 

Sooo.. I got the injectors yesterday, put them in this evening, fired it up - and no change 😕

So now Im back at square one, the car is running incredibly rough, and I have to balance with the throttle to make it run at all..

Any input or suggestions for where to take it from here? I’m running out of time as I have to get the car in storage before winter hits..

Thanks guys!


Ken

 

During the power-balance testing, which pair of cylinders had no reaction when the injectors were disconnected? Those would be the focus, checking both ignition and compression or cylinder leakage in those holes.

 

Thanks for your input Vader!
It was cylinders 4 & 6

I will proceed with checking spark, then get me compression & leak testers if ignition isn’t an issue

Thanks again man


Ken

 

Alright, so here is an update,

I checked spark on one of the fouling cylinders, and had spark with a spare plug, but poor to none on the installed one. So, obviously the spare set of plugs I had swapped initially with was not good
So yesterday I got a set of new ones and it immediately sounded better and ran on all cylinders when running, yet still unsteady. But I kept at it until it warmed up, and then it actually ran smoother than in a long time - just with a high idle - but at least it would run fine on its own.

However, when starting it again today when cold, it would not run at idle again, and I have to keep easing on and of the throttle to keep ut running, but it does run on all cylinders.

So one problem is solved, but not the idle problem.

I've attatched two scans - one from yesterday when it had warmed up and was running smooth - and one from today when starting it cold and not able to idle.
Any of the readings give any pointers ? Or the fact that it does this only when cold ?

Since it ran smooth when warm, I have not bought compression & leak testers yet, would that still make sense to do, or just a $200 waste at this point ?

Thanks!


Ken

 

If it has a smooth idle when at operating temperature, it should be safe to rule out the mechanical problems that would be diagnosed with a compression tester or cylinder leakage test. My guess is that the valve train and cylinder sealing are intact.

I haven't looked through the scan logs thoroughly, but I do note a persistent Code 44 for a lean oxygen sensor.

 

Exactly what I was thinking, that it doesn't sound like a mechanical issue at this point.
I have also noticed the code 44. I've checked for vacuum leaks but I'm not confident I have ruled it out completely, so I was going to get me a vacuum tester today. Or does that not make sense since it runs smoother when warm ?
Last night I drained the gas tank and added fresh fuel to rule out bad gas as I read that water in the gas could also be a cause of lean condition - and I did get gas the last time I drove the car before it started failing.

I've also seen a bad ECM could be a cause of this. But right now I feel I'm just throwing $$ at it with guesswork rather than a good plan


Ken

 

Sooo, it’s spring, car’s out of storage and problem of course still the same unfortunately..
Had a tiny hope that it would just be a clogged fuel filter, so replaced it today and problem remains.

I managed to drive the car about a mile or so from storage and home, but there just is no power. After it warms up, it can almost idle ok, but as soon as I put it in drive - it starts stuttering and I have to balance it with the throttle.
To get uphill I could only drive it in 1st or 2nd gear, once hitting 3rd it just loses all power.

Im at a total loss here as to what to do next.. Hate just throwing money at it, so any thoughts would be highly appreciated.

The way I see it, the only things left basically is distributor cap/rotor/coil and ignition module, or the fuel pump..

Any thoughts?

Thanks!
Ken

 

Hey guys,
I'd really appreciate your thoughts -. I seriously have no idea where to go next with this piece of &/&%#&..!
If I didn't put $12K into paint&body last year, I'd consider just giving up on this now and get it out of my way, it is driving me insane!

So this is a summary of what has been done up until now since it started acting up last fall:
Replaced:
IAC
TPS
IAT
Injectors
Plugs
ECU
Fuel filter
Fuel pump relay + pig tail
MAF burn-off relay + pig tail
MAF power relay + pig tail
Some vacuum lines
Complete new distributor (including coil/rotor/cap/ignition module/pickup coil)

In addition I have:
Set the timing
Set IAC/TPS
Checked vacuum with gauge
Drained and replaced gas
Cleaned TB

Current status is that it still starts, runs somewhat decent when balancing it with the throttle at around 3000 rpms. It is not possible to keep RPMs steady with holding the throttle still at any position, it will surge no matter what. Only way is to keep barely revving it. It can run some on its own once heating up a little, but doesn't need to reach full operating temperature. It will then sit fairly steady at 12-1500 rpms for a short while before slowing down after a while. Then it will start stuttering and surging again. To get it to smooth out some again, I have to give it a good bit of throttle. Just a little throttle will kill it and it will stutter/surge and occasionally get these hard knocks/backfires or whatever it is... Turning it off and starting it right away again, will always briefly smooth out how it runs.

I do have a new EGR valve that has not been installed, and also a fuel pump. The FP I really don't want to tackle unless there are clear indications that this can be it..
I also started wondering if it could be a stretched timing chain. It may have 30K miles on it at the most - but 20 years...

Any of you guys have any input that can help me narrowing this down or eliminate some issues ?
I currently have thrown well over $1500 into trying to fix this crap - so again, any help would be highly appreciated


Ken

 

I didn;t see anything about fuel pressure......


Mine used to run like that when the fuel pump was going bad.... it still oddly showed good pressure though.......


then one day it just crapped out 10 houses up by the cute girl's house...

SHAAAAAAAAAAMMMMMMMMMMEEEEEEEEE!!!!!!!!!!!!!!!!!!!!!!!!

 

So, here's a possible idea: the EGR valve and/or solenoid are malfunctioning in such a way that the valve is stuck partially open, which could lead to poor idle. I was informed of this as a possibility on a TPI facebook group.

 

Thanks for your input man! Fuel pressure reads "steady" at 40-46, depending on throttle - so it appears OK. But is it possible the FP is still the problem ?


Ken

 

Thanks a lot for your input, Komet! And, well, I have the new valve - so might as well dig in to get it replaced and see how it goes.


Ken

 

BTW, I also have a new knock sensor. Any way to rule it out before pulling it ?


Ken

 

I remember reading something about pressure vs actual volume the pump can flow. Im not sure how to measure that though... but supposedly good pressure doesn't mean good volume... that was Im guessing the case with mine as the pressure was always good. until it crapped out suddenly. So im thinking i had poor volume....


Try disconnect the EGR if you can reach it and see if it runs any better. That will rule out the solenoid sticking. I think ti should be able to run if its partially open. If its fully open though then it may have running issues. like the ones you have... you can try apply vacuum to see if it holds vacuum and also shove a mirror under there to see if its stuck open. before pulling everything..

Revving it up though would make it run better if its stuck open i think since EGR opens up at higher engine speeds?

 

Dang man! Thanks for leading me down the EGR route - if that ain’t it alone, it certainly is part of the problem. I followed the steps suggested in this thread: https://www.thirdgen.org/forums/tpi/...r-without.html
Got me a vacuum pump and started testing. Not quite sure if the valve is good or not - but the solenoid is shot! Leaked like a ****, and upon close look, it is cracked!

Now, where the heck can I find a new one? Or am I stuck with getting a used one?





Ken

 

Fortunately mine was good so I didn't have to worry about it, but I believe your options are used replacements, or possibly a corvette one.

 

There are some threads about using a new I think 4th gen unit.....or I recall a Cadillac valve as well, but those might be discontinued as well as they were I think mid 90s parts cvalves.... or just deleting EGR from the prom

 

Sooo..an update..

I found that the leak was in the rubber part and managed to fix that with a crimp hose.

I checked the solenoid by applying 12v, and can hear that it engages. I also measure 12v on the solenoid connector, but when plugging it in - the relay does not engage.. Could it be a poor
ground, and do any of you guys know where the ground point is for it?

I’ve had the ground connections on the back of both cylinder heads off, cleaned and reassembled.

Since my last update I have also replaced the O2 sensor a second time, the temp sensor on the front of the intake as well as the EGR valve. I also tried a different chip… all while the problem remains..

The last 3 things I can think of is:
MAF sensor (but would expect a code)
Fuel pressure regulator (although it appears steady)
Fuel pump

Im so f***ing fed up and tired of this piece of crap!


Ken

 

I’ve been tinkering with the TPS, the IAC and the idle for a while now. It runs, but to get it to idle decently, the idle screw is all bottomed out, and I know that ain’t right!
However, with the TPS set within specs, it idles around 1000-1500 for a about a minute or so, then increases the rpms slightly, before going gradually down until it basically dies..
I can immediately start it again, and it does the same thing.

If putting in drive, it will hold the idle, but if I hold the brakes and give it a little throttle, it struggles..

Don’t know if any of this makes sense to you guys, but I hope so 😅

Ken

 

Latest update (not sure if you guys care to still read about this )

Replaced the fuel pump (remind me to remove the dude behind this tank design from the gene pool..) - issue still the same.

Will start right up, have to feather the throttle to prevent it from stalling. Will run at a very low very rough idle for a short while before stopping.

I’ve noticed the fan starts on cold engine occationally ? It stops when the engine stops, even of the ignition remains on. Is that a clue?

Again, would appreciate any input.

Thanks!

Ken

 

Is it still throwing Code 44? What happens when you disconnect the MAF?

 

No, no codes after replacing O2 sensor - but still runs the same. So Im guessing maybe the bad 02 sensor was more an effect of the problem than a cause?

Any reason to suspect a clogged return line?

Thanks!!


Ken

 

An update with videos of how it runs with and without MAF connected, and it actually idles fairly steady with the MAF disconnected??

With MAF connected, not touching the throttle:


With MAF disconnected, not touching the throttle:

Can it be the MAF itself that is faulty when I have no codes?

Thanks for any input!


Ken