Bentwings

I did rescan after the new O2 but other than to see that it is now working correctly the car still runs like crap. When we had it on the hoist the cats were nearly red hot. However I think they normally run 900 deg or so. That why they start grass fires.

it looks more and more like a vacuum leak. I arranged to borrow a smoke machine next week end. I’ll be moved by then so I’ll have more time to deal with it. I talked to a guy that has quipment to clean and flow test the injectors but he suggested to just go and purchase 4 new injectors and have him flow test them before I install them so we don’t get a bad one. Labor wise it’s not really worth it to just take the things out , put new o rings on them , clean and flow them. Just put the new ones in an be done with it. But I still want to confirm the vacuum leak first.

Bentwings

Update on this mess,

A smoke test was done with a brand new top if he line smoker. Showed no leaks. Then the compression was checked and all is fine and even. Didn’t get a number in the report however. Then another set of new plugs and right side wires were installed. The plugs were all badly blackened. Scan was exactly the same. The whole right bank is dead rich. There is low manifold vacuum too.

Just to side track a bit I did an experiment on a carb streetrod yesterday. He had a brand new Holley carb,Edelbrock RPM manifold and GM HEI. set the timing for 32 total 16 initial with the curve built in and vacuum advance. It idled at 700 nicely with 16 in vac. Adjusting the idle screws for max vac gained 1 in. so nice and smooth 17 in . vac. Then I richened each idle screw to get a very rich idle as my Buick has. Got it down to 13 in and very stinky, plus needed to turn up the idle speed slightly. This test was just to demonstrate some of what is happening. The Holley just ran rich then cleaned out as we drove however at lower speeds it would blow black as you stepped on it.

Back to the Buick.. The fuel pressure was checked again as well as the regulator. All seems ok. O2 sensors are operating within range. The car has new Cats. The exhaust system is clear and clean. The O2 wires look and test ok. Didn’t replace them so a question can be laid there. Everything has been reviewed again.

So we talked and agreed that that we should put new injectors in. We both hate to throw parts at it but there is enough circumstantial reasons to replace them. High hopes.....dashed. There was no change in the scan even after a road test.


So where to now?

We have done exactly as neither of us wanted to do and that throw parts at it. However we felt at each step there was reason to replace a part.
Right now there is no choice but to go after the computer. I’ve never had to replace a computer but I really have little experience with this, and certainly not this level of issue. There is a local guy who does reflash the computers. Since I’m really not familiar with these or the process I have no choice but to be lead by the nose ring. (figure of speech)
I was under the impression there is an engine control module and an EPROM. How these are related are above my knowledge but I sure would like to learn.

The reflash guy also does “computer rebuilding”. Again I’m in the dark. Certainly I’m familiar with personal computer restore and reload. I would imagine the car is something like this.

So the guy is supposed to come over either today or tomorrow.

I considered purchasing a “rebuilt” one and an EPROM from Rockauto. I didn’t even know this was possible. There is a hefty core charge too.

i suppose I could search the internet and see if there is a used computer assembly? around. I know there is a procedure to do the replacement but have not done it.

After all this no other shop even wants me to come near as I might have car AIDS or HIV’s.

So any comments most certainly would be appreciative.
Any comments would be appreciative.
That’s where we are.

Chimera96

are you sure you don't have a PS exhaust manifold leak/crack/broken bolt (fairly common #8)?

The PCM would read this as more air and dump fuel in that bank...

I seriously doubt the PCM itself is bad

Bentwings

Yeah, we have gone over every inch of the exhaust system looking for leaks. It’s been up and down so many times on the hoist that the hoist may need servicing for wear. Even the air injector reactor ports are plugged per GM TBS. no change.
its truly frustrating. Nothing makes better. However we will check # 8 specifically.

There is absolutely nothing that points to the computer except there there is nothing else to look at. I hate to say it but some parts were change on just guesswork, no good reason other than “maybe this will fix it”. The last thing we wanted to do.

I saw where one guy went through this scenario and just switched to carb with a controller for the trans. I don’t want to do this at all.

Chimera96

Not sure if you replaced the 4 injectors or not but if you did they would need to be the same brand, AC Delco, as the other originals. Other "same #" injectors will have different duty cycle and often spray pattern so PCM tuning would be required (like using 24# Accell injectors for example)

you can pull the fuel rail and with KOEO see if any of the injectors leak which would cause rich.

if you have not, you can swap the L&R bank and see if the rich condition moves over to the other bank which would indicate 1 or all of those 4 are bad

I have sent injectors to www.cruzinperformance.com for service with very good results. They send a B/A flow chart when they return the injectors. IIRC its about $15 a injector

Bentwings

Sorry I didn’t get back. It ran the same with new injectors. Sad. As I noted there was no place to go but the computer.. I still think there is a vacuum leak. Most likely the intake. We did talk about “just doing the intake” but it’s along with throwing parts at it. That’s turned out to be what’s happened. Even though we have discussed parts replacement.

I. Moved to my boat during all this so my laptop got put somewhere. I finally found it but not the charger. Also found the flash drive with the 4 scans and the adaptor for this iPad. The last time I tried to send them from here it didn’t work. The internet from here at the marina is terrible so I’ll have to get to a better spot. Maybe the library.

The guy that was supposed to reflash the computer said he couldn't do this one for some reason. So in the end we ordered a new remanufactured computer. I didn’t want to do this but there wasn’t much choice. I missed him last Wed and they were off for the weekend so I’ll either stop in or call first thing Tues on my way to work. I have a bad feeling that the computer did not solve it.

I really want to do a squirt bottle bottle with water around the manifold test and a vacuum test with the PCV circuit test. I still think there is a leak somewhere.

I also found that the BLM can be reset by disconnecting the batter for 30 minutes. I don’t think that’s going to help but maybe it would show something before it maxes out again. I don’t know.

i just wish I knew more about this system. I’m trying to learn but it’s not coming very fast.

Injuneer

The PCM can be reset (LTFT's, learned IAC counts) by simply pulling the “PCM BAT” fuse for 30 seconds, or using Scan9495.