Ok quick question, my brother built this 2.8 years and years ago, He put in a aftermarket cam, but cannot for the life of him remember which one, or the lift on it.. just that it was not stock, and the Heads he changed to give it more compression. But the ECM is still stock.

I am Having some issues.. getting my 2.8 to run right, Its sluggish, off the get go, and sluggish when you step on it.. Ive run Winaldl and logged it while driving. No codes are showing up.. Seems to be getting rich flags on the INT and BLM but Im gonna attribute that to stepping on the gas then waiting for 3-4 for the engine to go oh yea, lets speed up...

In your opinion do you think it be wise to get the ECM taken in and reprogrammed.. or get a Hyperchip for it.. Stage 1, 2 or 3 I have no idea what the difference is..

Last test run I did with Winaldl running and 10k resitor.. I got while driving.. INT of 189, BLM of 156 max values, doing 70MPH, MAF was 79.83, O2 got up .862 ... I got Closed loop, Rich Flag, Old High Gear Flag, and BLM enable flags...

Haven run a injector drip down test on it yet, thats this weekend.. I think..

Thanks in advance

With INT and BLM numbers like that, you are lacking fuel, a large amount of fuel.

Check fuel pressure and the injectors, to make sure they are all working and not blocked.

Ok thanks, Ill pull out the injectors tommorrow and see what they look like..

Fuel pressure is 41PSI .. 20 mins later was around 37ish...

IAC is clean, and moves in and out, Seafoamed the intake few days ago.. MAF was checked and clean, no warpage or bubbles on the board. Voltage to is 5.05volts, same for all other sensors.. MAT was showing 4200ohms cold, at 65F .. TPS was sitting at .61volts idle, I guess I could tune that down a bit to the correct .50 volts..

Those are pretty high int blm numbers. Laking quite a bit of fuel.
What does the nb o2 look like when you mash the gas and are in open loop?

Id ask if you saw any spark knock but im pretty certain the ole 2.8L did not have knock sensors.

it could be so rich that its giving false lean readings.

what do the spark plugs look like white or black?
verfify the ignition timing


i doubt the cam is to blame u can slap a 272 grind cam in a 2.8 and it will still run pretty decent with everything else being bone stock

Well the spark plugs are mostly on the tan side, and compression is 122-124 ish range, just did a quick test, and a leak down yet, Have to run off to a chrio appointment... Timing was re done last night before the test, disconnect est wire, set to 10, pull ecm fuse, wait 30 secs, reconnect everything...

How old is the O2 sensor?

Also has it been replaced since the engine was run after the rebuild?

I have found many times that an O2 sensor will die very quickly after a fresh rebuild, I have theories as to why, but haven't found any really good reason. And it's because of this that I usually install an old O2 sensor for the first few hours of running as a sacrificial O2 sensor.

Well a little tinkering it got a tiny bit better.. Used to stall on start up, or hard to start. Readjusted the Dist, and she started right away this morn.. She still surges though.. Its still hunting for the right, fuel mix. First 15 secs it will surge, then settle off after that.

I replaced the o2 sensor this morn and ran a few more test.

I should note that my earlier posting of compression was off, compression is 135-138,,, not the 122-124 I listed..

On initial start up for the first 15-20 secs, BLM and INT are within 128.. After warmup, coolent at 203f, INT/BLM climbs to 139/156 .. Went for a short run around the block, 4 miles. INT/BLM rose to 174/156 .. O2 reading was maxing out at 0.999 volts,

does the car have headers? if so u may need to install a heated o2 sensor

No stock cast .. Y pipe, then O2 sensor, No cat, it was cut out before I got the car..

BLM/INT will always be 128 when in open loop, at initial start.

Have you checked the fuel delivery yet? fuel pressure when running, and whether the injectors are ok?

The O2 voltages show that it barely gets above stoich, and remains on the extremelt lean side of reading.

Have you tried a different ECM? There is a possibility that there is an issue with the O2 circuit in the ECM, causing a false lean condition. Also check the wiring to make sure that none of it is fraid and possibly being pulled towards ground because of that.

Checked fuel delivery, but not while it was running. I was going to and just got ahead of myself.. Ive pulled the Upper intake off and fuel rail now. Gonna just install new injectors. These ones were reused and have at least 200,ooo miles on them.

I have checked the wiring, and as far as I can tell its clean and no shorts. I totally stripped the car last year to the sheet metal, (in the engine bay, I pulled the engine wiring harness through the body into the cabin.) I did check it again when I reinstalled the new O2 sensor, no shorts found.

Gonna pick up 6 injectors, tonight, and see how that goes. I just replaced the fuel filter, last fall.

After Im done with this motor, I have a 3800 SSeII supercharged to help my brother install and get working in a 1985 2 door chevette. All this trouble shooting is not going to waste and I appreciate your help

well Installed the new injectors today, and Ive gotten rid of about 90% of the hesitation.. I know they did help a lot.. Before when I stepped on it to pass, it would think about it, and maybe go.. Now you step on it and it accepts the throttle response. Its not throw you back in your seat from a 500hp motor, but enough for a little v6 pulling 3500Lbs..

I think I will swap out the exhaust.. The previous owner cut out the cat and scrapped in in a bunch of stell. Y pipe goes from like 2.5 down to 2ish and back to 2.25 inchs to the muffler.. If I can get a little better flow there would help

Also, not sure, but maybe a Hypertech chip set up for a Manual and premium might help as well. Its not expensive, like 100.00 And right now the ECM is stock and still thinks it has the automatic tranny.

I Appreciate the advice Sixshooter, and project89 Ill keep ya posted

Don't waste your money on one of those off the shelf chips, not worth it in the least.

Your better off getting a programmer and learning how to tune it yourslf.

Good advice I did a little reasearch after I posted, and found most didnt find a improvement in them. Better off doing headers and exhaust ..

expect for the exhaust, which I still havnt made up my mind on, it will be the last upgrade for this year.. between the stereo, I installed, and the engine parts. my budget is done.

not sure if you've seen it but my camaro is over in member's area.. https://www.thirdgen.org/forums/memb...ort-coupe.html

Thanks again sixshooter