Rough running

[mongoosetoo]

My 85 GN powerplant in a Cutlass doesn't seem to want to accelerate. Idles fine, but fails to accelerate without popping and generally seems to have no power. Cmon I know this is only as hot-air engine, but it should still pull like a freight train.

Brand new engine, internal engine probs (like cam timing) are probably not the problem. But I'll pull a leak-down test and check compression - post later.

I have verified the vacuum hose routings.

The code my ECM says is 22 TPS low. I checked voltage at the center wire to ground: .42 volts at idle and 4.11 at WOT, so the TPS seems to be working - unless it's intermittant. I've got a new Holley one coming, but I don't think it'll do the trick.

Any thoughts? This harness was transplanted as well, I'll try to trace TPS wires back to thier source to look for breaks or shorts. In the mean time, if anyone has a reasonably priced Turbolink setup, I think I can get a better picture of what's going on. I have a laptop, I just need the software and hardwire hookups.

Thanks, Brew

 

[mongoosetoo]

Just changed the fuel pressure regulator this afternoon. The old one did range from 28-38. I tested it with my Mityvac handpump, without the engine running and even though it made the pressure stay in range, the vacuum would slowly leak off. I had a spare so I installed it. It does not leak off. Still, nothing changed about the car. I checked the TPS again, I have 5 volts coming in on the wire on the driver's side of the plug and have .42-4.11 coming out on the middle wire. The ground seems fine (the pass side wire).

Any thoughts? Also, now the car will not start at all. Tries to, but doesn't quite start. It gets to the point where the engine just barely outruns the speed of the starter enough to disengage and then dies. I have to go to school tonight so no more time to play with it today.

I'm open to suggestions.

Thanks, Brew

 

[BRAD_PADGETT]

Do you have a MAP sensor?- Brad

 

[FWD turbo]

For one thing, 4.11 tps at wot is too low. The ECM won't recognize that as WOT and you won't be getting AE. I think it has to be a minimum of 4.5 at WOT for the ECM to recognize WOT. Mine is set at 4.9. Not sure if that is your only problem, but it is definitely A problem. You need to reset your TPS.

 

[mongoosetoo]

I'll reset it and get back with you. As far as Brad's reply, are you asking me if I have an extra MAP sensor, or suggesting I try swapping mine?

Thanks, mongoosetoo

 

[mongoosetoo]

I was just thinking, is there a circuit that prevents the turbo spooling up unless the car is in gear? I was just thinking because I put a B&M prostick in the car and haven't wired anything to it yet. All I did was install the mechanical side of things.

As far a Brad goes again, I think you are trying to tell me to check/change the MAP sensor. That would certainly make the car not start if senses no manifold vacuum. I'll run to Autozone and get one.

 

[FWD turbo]

If you are using the ECM from an 85 GN, you don't really need to worry about the MAP sensor. It's only function in those cars was to operate the crappy light-bar boost gauge in the dash. If you check the wiring schematics, you will see that the MAP sensor isn't even connected to the ECM. So save your money on that one and spend it on something else!

Any progress yet?

 

[mongoosetoo]

thanks, I just got back from the auto parts store with a new MAP sensor. Turns out they gave me the wrong one anyway. So I'll return it and not buy another.

As far as progress, when I was out checking the MAP, I tried to start the car again. Still does not start. Still acts like it wants to, but just can't outrun the starter speed enough to run.

This car was running two days ago, it was running rough, like my original post says, but now I got nothing. I did reroute all vacuum lines to original factory diagram, but the car was running after I did that too. Just all of a sudden it doesn't want to start.

I think I'll put an inline light on one of the ignition wires to verify spark. I smell fuel, so I know I have gas.

One more thing, when I found code 22 on the ECU, I tested the TPS and disconnected the computer plug out by the battery to clear the ECU memory. I plugged it back together afterward. Do you think erasing the code could have caused this problem - I mean I don't think it would, but is that anything I should investigate? Currently, I have no codes on the ECU.

Thanks, Brew

 

[BRAD_PADGETT]

I have the original shop manuals and can send you the steps to track down a code 22 TPS. The manual says that the TPS is one of the most important sensors on the car. What ECM are you running and did it come with the engine? Let me know if I can be of further help. Brad

 

[mongoosetoo]

Thanks Brad, I'll check the ECU #. It came with the motor, pretty sure it's the right one, but you never know.

Also, earlier tonight I checked fuel pressure again as I had changed the press regulator because my old one was leaking. The spare I had showed pressure ranging from 45-36 depending upon how much vacuum I was pulling with my Mityvac. Big difference from the original. I'll pick up a brand new regulator and mount it tomorrow and get back with you.

Also, I checked spark. I have one of those inline jobbies that lights up when current passes through on its way to the spark plug. It does light up just fine. SO I know I have spark, so I'm thinking I may just be flooding because of the higher fuel pressure. That would explain it not starting and the slight fuel smell up front. I'll change the regulator, check a spark plug or two for fuel foul and check the ECU. It may take me a couple days, but I'll try to get to it tomorrow.

Also got a package from Summit Racing yesterday, supposed to be my new Holley TPS but they sent the wrong part. Wasn't thier fault, Holley marked the box wrong. Anyway, should have a new TPS by Monday.

Thanks for all your help. Brew

 

[mongoosetoo]

Thanks for all your input so far.

I changed the pressure reulator today and did a leak down test on injectors. Everything is as it should be now (28-38 PSI.) And with the fuel pump off and manifold pressurized to 38 PSI, I could see the guage drop and stop about 3 psi at a time while I cranked the engine without starting. I figure that tells me the injectors are opening and closing as they should. And I do have spark, per last post.

Then, I changed plugs. When I did, they were all soaking wet with fuel, one or two even dripped. Good thing I changed the regulator. So anyway, as I changed the plugs, I took compression readings from the cylinders. I came up with the following numbers:
1-120 2-100 3-106 4-79 5-84 6-45

Yikes! This is a brand new motor and one of three things have happened here, let me know if you agree/disagree. Anyone else feel free to chime in as well.

One, I have less than 45 minutes on the engine yet, hopefully the rings just haven't seated. I'll try starting it again probably Saturday and see what happens.

Or two, the excessive fuel washed the oil from the cylinder walls and glazed the walls. The motor will have to come back out, be disassembled and deglaze the walls.

Or three, I built this engine about five years ago and it has been moth-balled ever since. The valve springs could have lost their tension, but I really doubt it. At least not enough to create those kind of numbers.

That's a huge difference in cylinders. Optimal readings should be within 5% of one another. 10% is acceptable, but this is huge. 120 psi to 45 psi, ouch! I sure hope the rings haven't seated yet.

I also checked the service number on the ECU, not sure which number you are looking for so here is all of them: 1226459 CMM 866324 M511854414

Hopefully these numbers ring true for an 84 or 85 T Type.

I am and have been an ASE Technician for about 16 years. Over the past four or so I have gotten out of it and perhaps lost my edge. I'm embarrassed to admit the following....

When I disconnected the ignition wires, I lost my place, so I pulled out my diagrams and found something really stupid. I think if I had an idiot light installed on my forehead it would be bright red about now.

All along, I had the wires from the ignition coil pack switched . The even bank and odd banks were swapped somehow. Like I read the diagram backwards or something. I'm surprised the thing ran. That would certainly explain the lack of power and backfiring.

I would have had it back together today, but that #6 plug is a bear - as I'm sure you all are aware.

I'll keep you posted, maybe Saturday I'll have it back together. Thanks, Brew

 

[BRAD_PADGETT]

Slow down and relax. I have an 85gn and just converted to the 86/87 ECM. I ran into alot of problems which have been resolved. Check my posts on GNTTYPE.ORG under hot air. The ECM you have is the correct one for an 85TTYPE/GN. The problem is most likely the wrong chips. GM used the same ECM on all different cars and used different chips for each individual car.
The ECM has a large chip and a small one called a Calpack. I cannot find my original large chip but my calpak chip has a different number. You need one that ends in 6504 or 6505. This leads me to believe that the large chip is wrong as well. When I converted to the 86/87 ECM I had the wrong chips(actually from an six cyl FWD) and the car would not start. I have an ULTRA chip for an 85 ECM if you want it. Brad

 

[FWD turbo]

What is an ultra chip Brad?

 

[Jerryl]

........I think if I had an idiot light installed on my forehead it would be bright red about now.
All along, I had the wires from the ignition coil pack switched . The even bank and odd banks were swapped somehow. ......... That would certainly explain the lack of power and backfiring.

Brew,
Do not beat yourself up! There are plenty of other people in life who will
We have all "been there done that" on stupid stuff. It is part of learning about these cars.

Besides, the wire switching “front to back” on the coil was not a dumb thing. The "waste spark" system (As is the case on many motorcycles) would allow you to switch the wires and still run! See, 2 cylinders will spark simultaneously, only one is at compression and the other on the exhaust stroke. That is why in fact it will run!

Now, not trying to insult your intelligence but here a few things to think about.
Now regarding the compression variances ...... THAT is an issue. You may now need to rely on a leak-down tester to determine the
cause(s). I doubt you have any valve spring issues form "just sitting" but I have been wrong before.

If any rings were broken during the assembly, you will need to pull the motor before there is any significant damage to the cylinder walls. Cylinder washing/glazing IS an issue if the plugs were wet, but then again, you already knew this.

Take the valve covers off and see if there are any broken springs, AND, make sure the valves open all the way. Highly unlikely, but ......... 30 minutes of cranking and no oil could have done some damage to the cam.

 

[BRAD_PADGETT]

An Ultra chip replaces the stock chip and has a wheel to change the spark timing based on what type of gas you are running. I will try to find my stock 85 large chip today and get the number. Brad

 

[BRAD_PADGETT]

Here are the correct chip numbers-Calpack end in 6503 or 6504. The large chip has a sticker with CMM 1865. Brad

 

[mongoosetoo]

BRAD- I'll check the chip number and configuration and get back to you, thanks.

Thanks guys. I just finished putting it all back together. It does run now, still somewhat rough, but as it warmed up more and more, it began smoothing out. Slowly, pass after pass, I was able to achieve greater speeds and allow the engine to progress further and further into the RPM range.

Currently, I do not have a tach on the car and the cluster led bar thing isn't lighting up. So I'm not sure about RPM or Boost pressure, but I would have to guess I'm able to see about 4500 rpm right now. That's a whole lot higher than I could see on it last week.

With all this new data, I would have to say maybe the rings are beginning to seat and compression coming up now. I won't know unless I take the plugs out - so for now I'm sick of pulling plugs and I'll continue to run it up and down the road and monitor the performance.

Last night I downloaded that free Turbometer software and built the plug and harness this a.m. I'm stuck babysitting, but I'll hook it up to the car when the wife get's home. My laptop doesn't have a serial port on it, but I have a regular desktop out in the garage I'll plug into, i just won't be mobile.

I'll keep you all posted and thanks for all your input.

 

[mongoosetoo]

Just tried the Turbometer and it does not work. I do recieve some sort of data from my car, but it says I'm running 175 mph. It does not pick up anything else properly as well. With the car idling after a test run, it said it was sitting on 182 degrees temp and did not fluctuate at all for 15 minutes. None of the variables are coming besides those.

So either I did something wrong, or something in the car is actually wrong. I'm d-loading WinALDL tonight and trying it tomorrow to see if anything changes.

As far as the car goes, still does not run well at all. It will get up to about 50 mph if I take it slowly. But generally spits and pops most of the way through.

It does start easily now though. Yippee.

Anyway, I'll post again tomorrow if I have time telling results of WinALDL.

Bard- I forgot to check ECu number, I'll get it tomorrow. Thanks.

Thanks ya'll. Brew

 

[mongoosetoo]

Also forgot, what are the idle and WOT settings for the TPS. My new one should be here any day now and want to be ready to install.

Thanks, Brew

 

[buickpower]

have you tried resetting the cam sensor? also is it the original stock cam?