Engine Cuts out and stumbles under boost...HELP PLEASE! `

[TurboBuRick]

O2's are pretty solid until duty cycle starts going nuts. I don't see it being the fuel pump. The erratic duty cycle point to something else.

Cam sensor problem is a good possibility.

 

[Nero328]

I added one to my OG post... coil pack cinched down......

Chased it for about a month.......


RRRRRRR shift, WTF... RRRRRRRRR shift WTF...... And so on.

Someone else asked me about that the other day so I checked it and of course now that I had to change a head gasket I just put it back on and made sure to pay special attention to that when I put it back together. Yep, it is solid and I even ran a separate ground strap to the Coil Module attached at the base this afternoon just to make sure everything is grounded good. I also have a Caspers ground kit on the car.

 

[Nero328]

O2's are pretty solid until duty cycle starts going nuts. I don't see it being the fuel pump. The erratic duty cycle point to something else.

Cam sensor problem is a good possibility.

I am going to check that first thing in the morning, I will wire up the FP gauge to the PL and go out and get another log. I just hope I dont have to do that very much be

 

[TurboTGuy]

Someone else asked me about that the other day so I checked it and of course now that I had to change a head gasket I just put it back on and made sure to pay special attention to that when I put it back together. Yep, it is solid and I even ran a separate ground strap to the Coil Module attached at the base this afternoon just to make sure everything is grounded good. I also have a Caspers ground kit on the car.

Dang.....

Well, all I can say is good luck. The best part is, someone here will have the answer. Eventually.

That's the cool thing about this board.

 

[No disintegrations]

With some doubt about the fuel pressure still, I think you need to drop the tank and have a look there. Before. That maybe try to collect fuel volume at 60 psi. Unhook return line. Run reg shop air at 17 psi to the reg vac hose. Or your set boost amount. Then run fuel pump , collecting the fuel. Weigh it and see if it jives with horsepower you expect.

 

[Ttype6]

With some doubt about the fuel pressure still, I think you need to drop the tank and have a look there. Before. That maybe try to collect fuel volume at 60 psi. Unhook return line. Run reg shop air at 17 psi to the reg vac hose. Or your set boost amount. Then run fuel pump , collecting the fuel. Weigh it and see if it jives with horsepower you expect.

There's no evidence of a fuel delivery problem.

 

[RmvBfrFlght]

I haven't read pages 9 & 10, but in the second log at frame 175 of 261, the O2 sensor value drops to zero prior to you lifting off the throttle. I'd say there is a fuel delivery issue or the ignition is just stopping:

RemoveBeforeFlight

 

[Nero328]

I haven't read pages 9 & 10, but in the second log at frame 175 of 261, the O2 sensor value drops to zero prior to you lifting off the throttle. I'd say there is a fuel delivery issue or the ignition is just stopping:

View attachment 300662

RemoveBeforeFlight

A friend of mine and I were talking last night and we noticed the same thing. It is almost as if the ignition is just turned off which makes me wonder if perhaps a wire was pinched or something during the install of the motor. I am going to chase down all of the wiring this morning and take the time to wire up that FP regulator so we can see that on the log as well. I have chased all of the known culprits down on the wiring (Starter cable which is new, ground cable which is also new, main harness grounds and the fuseable links.) it is as if either the G-Force or something moving in the engine area due to torque is either pinching a wire causing a short or something like that. I will take the time this morning to sort all of that out and report back on anything I find. If that doesn't do anything then I will post a new log that has FP in it.

 

[achalmersman]

Just for reference,this is what I expected to see when I heared the engine dies / feels like somebody turning the key off and back on / we thought you had non-resistor plugs.

This is what it looks like when you have a ECM rebooting

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[Ttype6]

This is the screen shot that contains the most significant evidence. It shows erratic engine speed information being given to the computer and erratic adjustments being made to the injectors based on the erratic input. Until we see fuel pressure fall,we have no evidence of a fuel delivery problem.

 

[Ttype6]

Ok,how do you post a screen shot?

 

[achalmersman]

If your only using 1 screen you can click print screen and then post in paint and save as jpeg. If your using windows 7 8 or 10 you can use the Snip it tool and create a jpeg. I did it from my phone logged into my PC at home

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[achalmersman]

No trees were harmed in the sending of this message, however, a significant number of electrons were terribly inconvenienced.

 

[Ttype6]

I haven't read pages 9 & 10, but in the second log at frame 175 of 261, the O2 sensor value drops to zero prior to you lifting off the throttle. I'd say there is a fuel delivery issue or the ignition is just stopping:

View attachment 300662

RemoveBeforeFlight

What is not shown in this snapshot is rpm also falls while throttle is steady. Rpm is input information used by the computer to make decisions. When the computer sees the rpm fall it reduces injector on time. Bad information leads to bad decisions. The engine speed information given to the computer is erratic and incorrect. This is where we need to look.

 

[TurboBuRick]

I haven't read pages 9 & 10, but in the second log at frame 175 of 261, the O2 sensor value drops to zero prior to you lifting off the throttle. I'd say there is a fuel delivery issue or the ignition is just stopping:



RemoveBeforeFlight

I see what you mean on that log.

This is the one I was looking at. The IDC starts going nuts then the o2's start dropping.

 

[Nick Micale]

After the fresh engine was installed and many other mods including a billet fuel pump sender, lines and wire harness, we conducted a few road test sessions with a Powerlogger to accumulate data.

All was fine and normal as we increased boost for each boost session.

The final road test was at 18 psi and the car pulled like crazy w/o any discrepancy, and we have those logs, so it was parked until the owner arrived.

After a couple road tests with the owner, a most unusual issue happened which I have never experienced in 30 years of dealing with these cars.

He was driving, and my local friend was logging with the laptop, and during a short burst of power the GN lost all electrical power and died on the street. I do not know if there was a backfire or not, but there was no electrical power from the starter?

I have not ever seen a starter or solenoid fail, and not continue to pass power to the harness?

A replacement starter got the car running again, and is was not running well at all, and he found no.5 cylinder head gasket was torched which I would attribute to pre-ignition some where during the testing.

With the crazy and very unusual issue with the starter, there is a good possibility that the fusible links have been damaged which not allow ample current to be supplied into the electrical system?

An interruption of electrical power at high RPM can and will cause a damaging backfire at RPM.

I feel very bad for Mike as he is a great guy and having to deal with this, especially since it was running so well for us.

 

[Nero328]

Ok guys...now I cant get a signal to the PowerLogger from my FP gauge. I tapped into the signal wire (which is white in my case) and I am getting nothing to the PL. Suggestions?

 

[Ttype6]

I see what you mean on that log.

This is the one I was looking at. The IDC starts going nuts then the o2's start dropping.




View attachment 300666

Yes,this is what I'm talking about.

 

[Ttype6]

Suggestions?

Cam sensor. I would like to eliminate this as a possible cause.

 

[achalmersman]

Ok guys...now I cant get a signal to the PowerLogger from my FP gauge. I tapped into the signal wire (which is white in my case) and I am getting nothing to the PL. Suggestions?

Where did you connect it? Has to be i4 or i5 which is terminal 5 and 8.



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