92 Bonneville, barely runs

Im working on a 92 bonneville. will start up for a second, chug, die. give it about 3/4 throttle and it will start and run fine as long as I keep the RPMs pretty high but when I let the RPM drop, it smokes black, chugs bad, misses, etc. Code 41 (cam sensor). Replaced and same results. Any ideas?

did you check the interruptor magnet that goes in the cam gear that the cam sensor gets it's signal from? It's a common problem for the plastic retainer that holds it in the cam gear to get brittle and fall apart. This in turn causes the magnet to fall out and trip another cam sensor code.

Does the above symptoms point to a cam sensor problem? By what I understand, the sensor just helps keep everything in time. It seems like at the lower RPMs (2500 and under) its dumping too much fuel.

I looked up code 41 (no distributor pulses/cylinder select error). That would indicate a bad crankshaft position sensor or ignition module, not cam sensor.

I looked up code 41 and the "no distributor pulses/cylinder select error" is for non 3800 engines. 41 for 3800 up to 93 shows camshaft sensor. maybe im wrong. anyways, I changed the crank sensor this morning and it fired up and ran fine (as it has since this problem occured, it will run til it warms up a bit, then cuts out, smokes black bad etc) and then after 3 blocks, it died again. Towed it home once again and swaped the ignition module. Same results. sigh.

Ok when it won't run got spark and injector pulse? Disconnect maf and see what happens.

Ok, today I was digging into it more and I pulled the cam sensor and got a little mirror so I could actually see in the hole. what I saw was a 3 sided piece of plastic...no magnet. the other day when I felt for the cam magnet I must have just been feeling the plastic retainer. I assume this is my problem. Anywho, I have 2 questions. 1. Where do I get a retainer and magnet? 2. Do I have to pull the timing cover and such to replace it?

Well...you can do this: http://6007.us/cammag.htm

Or...yeah, you can pull the front cover off. The magnet is really cheap, 5-10 bucks, and can be gotten at autozone or oreily or similar.

AC-Delco part number on the magnet is 25530386, dealer retail $13.31

Ok, today I tore into it changing the magnet, timing chain and gearset, oil pan gasket, etc and the problem remains. Started right up and ran perfectly for about 5 minutes then chugged and died. Will start up upon placing the accelerator at about 3/4, but runs poorly and wont run in the lower RPMs. Black smoke. Please help me!! Im totally lost now!

Ok, today I tore into it changing the magnet, timing chain and gearset, oil pan gasket, etc and the problem remains. Started right up and ran perfectly for about 5 minutes then chugged and died. Will start up upon placing the accelerator at about 3/4, but runs poorly and wont run in the lower RPMs. Black smoke. Please help me!! Im totally lost now!
Well I wanted to say the cam sensor didn't match your symptoms. Anyway disconnect the coolant temp sensor see what happens, or scan it and make sure the temp sensor shows the proper temp when warmed up. If ok try disconnecting the maf and see what happens. Check for excess fuel pressure or fuel leaking into the vacuum line at the regulator.

Max,it looks like he's not reading your reply or feels he knows whats wrong.

no no, I am reading all posts and taking every bit of help I can get. This is the problem I have now. It dont start at all anymore. After the cam ger,chain, magnet change it started up and ran perfectly for about 5 minutes then sputtered and died. no start. It is firing somewhat. Put the timing light on all the plug wires and spark is irratic and not steady. Injector light is firing normal. Swapped the entire ignition module and coil set out with a set off a running and driving car....same results.

Im working on a 92 bonneville. will start up for a second, chug, die. give it about 3/4 throttle and it will start and run fine as long as I keep the RPMs pretty high but when I let the RPM drop, it smokes black, chugs bad, misses, etc. Code 41 (cam sensor). Replaced and same results. Any ideas?
did you disconnect the battery before changing out the sensor?

did you disconnect the battery before changing out the sensor?

Yes, I disconnect the battery before doing any work

.....still not running.....

maybe change your computer module...damn computers
I got 5 of them from the wreckers...there's ton's of bonnevilles in the wrecking yards in Alberta canada

I changed the ECM today, still no go. When cranking it will sometimes try to start, but the spark is too irratic to make it run. A quick recap

replaced crankshaft sensor (twice) cam sensor, timing set and gears, camshaft magnet, ECM, ignition module and coil set.

Scan it and see if you get an rpm reading when cranking, post back.

I had a 95 Bonny with wacked out problems like this, and I am the first to say it probably doesn't have anything to do with your problem....
But there is a ground wire on the ignition module, and I would recommend Checking Engine to Frame resistance. It should be very low 0 -10 Ohms. If not the engine ground.. although connected and looking like it is good could be bad.
I ran a new wire from Engine to H Frame, and a problem similar to yours went away.
:grinno:

I dont have the ability to scan the ECM. I would have to say that it is getting the RPM input because the injectors are firing on time, every time

I dont have the ability to scan the ECM. I would have to say that it is getting the RPM input because the injectors are firing on time, every time
Agreed, try dropping the exhaust down, before the cat, also compression good?

did you make sure you had the timing gears lined up properly? It sounds like mis-aligned timing to me. When the ECM starts monitoring timing, and senses the cam and crank out of phase, it is trying to impart some timing retard to compensate, and is causing the car to die.

I am 99.9% positive I have them ligned up correctly. I didnt have to turn the crank or cam any to fit the new gears on and after I completed the installation, the car started up and ran fine for about 5 minutes.