A call for experts - 87 GN Cranking, firing weakly but never getting off the starter...

[turbokinetic]

It's been a long time since I posted here, and for that I apologize.

I have a question about an 87 GN. A neighbor stopped by and asked me to look at his car which he is trying to get started. He has rebuilt the engine after it sat with water in the oil and froze up due to rust. The car was running and driving with a headgasket issue. It was parked and then due to personal concerns, he was unable to work on it for an extended time.

After getting the engine together, it will turn, fire, but won't sustain its self running. As long as the starter is turning, it will "almost" start but not quite. When I first saw it, it would turn over and "kick back" against the starter. This is typical of ignition timing or firing order problems. We reviewed the instructions for the cam sensor which has been installed, and re-visited its timing. This stopped the kickback, but didn't get the engine running.

The sound if the engine is as if the ignition timing is retarded and the engine is firing so late that the energy is all spent out the exhaust. After about 15 seconds of cranking, the headers are smoking and the turbo is turning. He has spent a huge amount of time and money trying to get it going. Multiple ignition modules, cam sensors, ECM/chips, injectors, etc, have been swapped in and it has not changed anything.

When it's cranking and trying to fire, the intake has a strange noise to it. There is no backfiring or popping at all; just an "exhaust like" noise for lack of a better description. The cam is aftermarket, and is supposedly pretty "rowdy." I have no experience with these sort of cams, My car has a Comp Cams 258HR and there is no rowdy idle and it starts easily. The cam specs and the instructions we followed for the cam sensor are attached. Here is a video where we were trying to start the engine.

YouTube video: https://youtu.be/nGAUhxqoB18

Thank you so much for taking the time to listen and offer advice.
Sincerely,
David

 

[SCOOBY DOO]

If you're in doubt about setting the cam sensor, here's a vid from my channel how to go about doing it. I assume you have the cam/crank dots set correctly. I'll also assume the spark plug wires aren't mixed up.

 

[turbokinetic]

If you're in doubt about setting the cam sensor, here's a vid from my channel how to go about doing it. I assume you have the cam/crank dots set correctly. I'll also assume the spark plug wires aren't mixed up.

Thanks for the reply! The sensor he has, is equipped with a built-in LED; and he also has a LED breakout box on the ignition module. We did the timing per the instructions, and then using the GM book method that you're describing in the video. Before the first time I adjusted it, it had been way off. After doing it per the book, and per the sensor instructions, both those methods came out the same. After that we were able to get the "almost starting" as shown in the video.

I have my worries that the timing gear (cam and crank) may not be correctly timed. I wasn't present when the engine was put together. I'm just trying to help get the car going. I hate to suggest that the engine may need to be opened up again; but this may be the reality.

I just can't explain that intake noise any other way.

 

[BRAD_PADGETT]

What you have is Pandora's box. It could be just about anything. Such as crank sensor, the old crappy MAF, fuel pump, ECM, etc. I suggest you find a known Buick guy to go through the car to find it. Can be easy or really hard. You also need a scan tool.

 

[TexasT]

Does it have fuel pressure at the rail? 30-40psi or so. You kinda need a gauge but if you unscrew the cover wand push the schrader valve it should squirt.
Have you pulled a plug after cranking to see if it is wet with fuel?
While you have it out, lay it on the header to ground it and crank the engine over to see if that plug is sparking?
Crank sensor was mentioned above. Does it have the correct clearance and isn't hitting the sensor on any of the three "tangs" of the crank piece? Both sides need clearance, not critical, a matchbook thickness on both sides. Adjust sensor as necessary.
Can you hear the pump prime when you turn the key to run?

 

[turbokinetic]

What you have is Pandora's box. It could be just about anything. Such as crank sensor, the old crappy MAF, fuel pump, ECM, etc. I suggest you find a known Buick guy to go through the car to find it. Can be easy or really hard. You also need a scan tool.

I'm sorry not to have more information, but as said this car is not mine and I was approached by a neighbor to assist. Yesterday was the first time I had seen it. I have a lot of experience with the electronics from cars of this era, including N/A to turbo conversions on FWD 3.8 engines with tuning of the factory ECM to work with it. Not that this is directly related to the problem at hand, but it gives you some idea of my experience level.

There is a permanently installed fuel pressure gauge, with about 40 PSI indicated whenever the fuel pump is on. There doesn't appear to be any rub marks on the crank trigger ring, where the sensor would hit. We are seeing consistent flashes on the CCCI SensorCheck box, so I would expect the sensor is working. It also has strong spark. The plugs become a little sooty when extended crank attempts are made, but they are not wet. Several (several) sets of plugs have been tried. We changed for a set of basic AC Delco plugs yesterday as well.

The ECM/chip have been exchanged with one from another known running car. The known-running car functioned with the ECM from this car, and no change was seen in this car with the known-good ECM.

The same swap test was made with the ignition module. Known-running car worked with it, and this car had no change with the one from the good car.

My neighbor has a Delphi MAF and Translator which was in use before the original engine failure. He went back to a stock MAF trying to get the car running. The MAF in the video is brand new. It was similarly swapped with one from a known-running car. As with the ignition module and ECM, the running car ran fine with this MAF, and this car had no change with the MAF from the running car.

There are no DTC's shown on TunerPro RT when the ALDL data is read. There is also an engine speed and injector pulse indicated, but I don't remember the exact numbers.

I'm very confident in the setting of the cam sensor. We had two procedures. The factory manual procedure, involving positioning the crank at 25° after #1 TCC; and a proprietary procedure from the manufacturer of the sensor, where the crank is set on #1TCC, then the sensor cap is rotated to a marked position, which gives the 25° offset. Both of these result in the LED turning on at 25° if the crank is rotated back and forth through the 25° position after the adjustment is locked down.

We have two indicators on the cam sync signal. The sensor cap has a built-in LED; and there is a Casper's CCCi SensorCheck box connected at the ignition module. Both the lights agree with each other and fit the expected outcome of the procedure.

I totally agree this is a "Pandoras Box" situation. My neighbor has been working on this car for a year or more I believe. My main question and reason for the video is about the camshaft. I don't have much experience with "rowdy" type cams because, frankly, I really hate the way they sound. Not having dealt with these before, I don't know what sort of intake noise should be expected. To me, it sounds like the cam and crank are out of time - but I don't want to start disassembling the engine unless that becomes a reasonable cause, based on eliminating others. My concern is that the engine was timed with the keyway used as the crank timing mark, and not the dot on the crank sprocket.

I hope someone who has the same camshaft can give us some insight in how the starting is supposed to be; and if the puttering noise out the intake is normal or not.

My neighbor assembled the engine himself, after it sat for a long time due to a health problem. There have been a lot of hardships already. I can't just say "I think you timed it wrong" unless we have eliminated everything else. It's about to that point I'm afraid.

For good feels, I have attached a picture of the LeSabre Grand National I just rebuilt the engine in. It belongs to a good friend. About 6 years ago I did a turbo conversion on it, and shared the pictures here. It ran until last year when the headgaskets started leaking. Now it's all good again!

Thanks again for the good ideas.
Sincerely,
David

 

[turbokinetic]

Does it have fuel pressure at the rail? 30-40psi or so. You kinda need a gauge but if you unscrew the cover wand push the schrader valve it should squirt.
Have you pulled a plug after cranking to see if it is wet with fuel?
While you have it out, lay it on the header to ground it and crank the engine over to see if that plug is sparking?
Crank sensor was mentioned above. Does it have the correct clearance and isn't hitting the sensor on any of the three "tangs" of the crank piece? Both sides need clearance, not critical, a matchbook thickness on both sides. Adjust sensor as necessary.
Can you hear the pump prime when you turn the key to run?

Thanks for the reply. It came in while I was typing my last one.

He has a fuel gauge on the engine, showing about 40 PSI. The pump primes, and also runs during and after any crank attempt.

There is a strong spark, as well. We did put in brand new plugs yesterday, as those were a little bit soot coated but not wet.

 

[TexasT]

I would take the up pipe off and squirt some brake clean or carb clean in there and try to start it. If it pops and tries you have a fuel delivery problem. Those injectors could be stuck shut.
Dry plug leads towards that also.

 

[No disintegrations]

I agree. Sounds like it's not getting fuel. The brake clean test is a great way to confirm. If it fires right up on brake cleaner you know you need to zero on fuel system. Injectors could definitely be stuck shut as Tex said.

 

[TurboBuRick]

Turn the cam sensor a little at a time until it starts.

 

[mikestertwo]

Sounds like the cam timing is off a tooth or two. I had a friend who installed a cam in a Cadillac engine one tooth off and it sound about the same. Had low compression and had that strange popping sound. Do a compression check on it. If it's extremely low I would pull the front cover and check the cam timing.

 

[Marty Fairchild]

If you haven't all ready done so, I would perform a compression test.

 

[1986 Buick GX1]

One of the guys rebuilt his engine over the winter last year. In just that short amount of time the injectors were stuck.
He purchased and installed a brand new set and the car started right up.
He sent those out for cleaning and now has a spare set.

Maybe a bore scope can be used through the cam sensor hole to very cam timing if you have access to one.

More food for thought.

 

[salvageV6]

Ether try it while cranking. As mentioned could be injectors, should be a thread on how to click them with a 9 volt battery to test them or use a noid light for starters.

 

[michael evans]

Like a few other post, it sounds to me that the timing is wrong. Do a compression test.
What type of timing chain was used ?

 

[turbo87adam]

Check to make sure the crank sensor is in the correct slot. Should be in the rear slot if memory serves me right.

 

[SCOOBY DOO]

Flat out ask the owner if he lined up the timing gears.

 

[turbokinetic]

Guys, thank you all so much for the valuable information. Last night, I expressed concern that in all the cranking and "almost starting" the low oil pressure warning had never extinguished. We took the filter off and found it dry. Not wanting to damage the engine, I strongly encouraged him to take the oil pump drive out and prime the pump with a drill. We took the oilpump drive out of the engine and it was almost too stiff to turn by hand. The shaft and bushings were very dry from sitting. With that out, we used a priming tool and pumped the oil throughout the engine, several times. I left before he had the oilpump drive repaired.

Today he put the oilpump drive back in the engine, re-timed the cam sensor on top of it, and the engine started! It seems that the engine was put together without the lifters primed, and the combination of all lifters collapsed and the cam specification in use caused it to have valve timing / lift problems.

Again I was unaware of any of the build or even of the existence of this car until yesterday. He will put the engine's external parts back on and hopefully it will be OK.

Sincerely,
David

 

[TurboBuRick]

The plot thickens...

Really makes no difference what tooth the cam sensor is on. You can turn the sensor to make up for it.

 

[turbokinetic]

The plot thickens...

Really makes no difference what tooth the cam sensor is on. You can turn the sensor to make up for it.

Exactly. I think the issue was the lack of oil priming and collapsed lifters; combined with the extreme nature of the cam.