PontiacBonnevilleClub.com

Hey All,

I just picked up a beautiful 90 SSE from my best friend. It has been in his family since it was purchased new. The car has 173,200 miles on it and has been garage kept all its life. Other than a few minor issues that I was planning on addressing, ie. power antenae is stuck up, power mirror switch is not working, slight intake manifold leak, the car runs and drives beautifully and was a daily driver up until the past Friday with no real issues other than those noted by my friends wife.

Of course my luck being what it is, I put the car on the road yesterday and took it on a few errands for about a 30 mile run where I had to start and stop a couple times but mostly was cruising around 55-60mph. Just cruising for about 10-15 minutes at 60mph the car developed an odd bucking. When I tried to accelerate it didn't want to and when I pushed the pedal down it bucked a few times than proceeded to downshift from OD to what felt like 2nd. After a second of letting off the gas it upshifted than smoothed out. Came to a number of stops and the engine idled without a sound at 1000 rpm's. Shut the car off and ran an errand for about 15 minutes, went back out, started without problem or sound, drove for another 5-10 miles and it did it again, this time throwing a check engine light with a code 41. I know what the 41 is and I'm trying to understand if the 41 could be the cause or just a possible side affect of the bucking which to me felt like a transmission issue. When trying to accelerate it felt like the transmission was almost fighting the motor. My friend of 20 years noted that this had never happened when they drove it and I do believe him and assured him it didn't matter, I loved the car so much I would see it repaired which leads me here. Thanks ahead of time for any and all assistance. I am not the smartest mechanic in the world but while I wouldn't try to rebuild a tranny, I would certainly replace one

Mike

The code 41 could be the cause since the cam sensor is used for injector timing. There is a sensor held to the timing cover between the water pump and crank pulley, and a little rearward. That's the cam sensor. You'll need to remove it (just one bolt) and turn the engine over by hand and look for a nub on the cam gear. A mechanic's mirror or removing the passenger front wheel and fender liner will help peer through the hole in the timing cover. The nub is the magnet that the sensor "sees", and it likes to go AWOL. If it's gone, you can JB weld one in place or you'll have to remove the timing cover and cam gear to snap a new one into it from the back side (parts stores call it an interruptor).

So it could be the reason for the brief bucking. Thanks for the feedback. If I have to I'll take the timing chain cover off and do that as well but perhaps it's just the sensor itself.

It could be, but it's usually the magnet. Check out the wiring as well back to the larger loom. It can get worn.

What intake manifold leak do you have? There hasn't been much of an issue on these motors.

There is coolant leaking out of the gaskets on both sides between the intake and the cylinder heads on the tranny side. It has leaked very slowly on this car for the past year or so (ever since my buddy replaced the radiator with a 3 core and put in a new water pump).

Could it be the vacuum modulator leaking? That would cause a vacuum leak, and goofy transmission symptoms. However, I could be way off.

The modulator controls the line pressure and the TV cable controls the shift points. The code 41 is definately a cam sensor issue. Check for the presence of the interrupter and the condition of the wiring. The wiring goes into and out of the ICM.

Also check the coils, plugs and wires. Make sure the connector to the ICM is on snug, but don't overtighten.

Well, I removed the intake manifold and sure enough, both of the factory original gaskets were deteriorated around the coolant passages thus the slight leaking of coolant. Upon inspection of the upper lifter area the engine is very clean with no sludge buildup. I replaced all of the o-rings for the hoses running through the bottom of the throttle body and the coolant to manifold tube. Had alot of fun when I broke the thermostat housing trying to remove it (original t-stat from factory). Called the local bone yard and be blessed they had a 90 old's 98 engine on the shelf and I removed one from it for 20 bucks. Degreased everything externally and removed a boat load of buildup from inside the t-body and manifold around the injector ports. Very interesting place to put the pcv valve which I removed and replaced as that was original also. I should have the rest of the intake back together today and than I'll run the car a bit before taking on the CPS. Spoke to my buddy and questioned on tranny servicing and he assured me they replaced the filter and fluid every 30k so I breathed sigh of relief. Prolly why the car shifts so tight still. More to come

Mike

If you already have the intake off, it is only a few more bolts to drop the oil pan and pull the front cover and replace the timing set, chain tensioner and the interrupter at the same time.

Did it a couple years ago on my 89 and the tensioner is plastic and was quite worn and I only have 139000 miles on mine.

viewtopic.php?f=8&t=1316

Well it's all back together (sorry, saw your post a bit late ) and I ran it. Runs good. Still posting that cam sensor so that will be the next hurdle. Figures I came down with a cold now and after working on it for 3 hours I'm to beat to start the new but maybe tomorrow.

http://bellsouthpwp.net/p/a/padgett46/cammag.htm

This procedure was written by one of our Gearheads, and is our standby in cases like these. I've done this on 2 cars myself (not my own).

I've decided that I'm going to replace the timing chain as well. Would someone give me a break down of everything that should be replaced during this procedure (waterpump is 6 months old so I won't be replacing that). What about the oil pump assembly? I also read of using a special tool for aligning the CPS, some sleeve that fits over the end of the crank? Is this required or is there another way to reinstall that sensor? Thanks all.

Mike

If you are using the same CPS, you shouldn't have to adjust it. Remove the bracket and the sensor comes with it. The sensor is adjusted on the bracket and the bracket is aligned by a pin in the cover.

Oil pump should be fine. You can open it up and check for any severe scoring, but usually isn't an issue on these engines. I would suggest doing the oil pressure kit from intense. It is listed for series I and II, but does work for us also. When re-installing the pump, pack it with vasoline so it can prime and will not run while dry.

You should replace the front seal. It can be stubborn getting it out, but just take your time and don't nick the aluminum housing. You can use several different items to put the new one in. I used a block of wood wrapped in a couple rags.

The timing chain tensioner.

Radiator hose if it is old, mine was the original from 89 when I changed it in 2008.

Oil pan gasket.

I think that is it, but others can chime in also.

I was also reading about the camshaft thrust surface and the possible need of replacing the cover. Any thoughts on this as well?

I replaced that too. The cover was fine though with 130k on it.

You replaced the timing chain cover also? Is the thrust surface removeable or part of the cover itself and lastly, how do you check it to determine if it is worn out?

Also. When replacing the timing chain, am I replacing 1, 2 or none of the sprockets? Will the chain tensioner come with with the chain as a kit or do I need to order it separate. Does felpro come in a kit for doing everything including the oil pan gasket? Crank seal? etc.?

Timing set will come with both sprockets and chain. Tensioner is sold seperate. For the cover, you just don't want to see a lot of wear. There will be some marks, but you don't want to re-use it if there is any deep gouging. The timing cover gasket set only comes with the front cover gasket, front main seal, waterpump gasket and oil filter adapter gasket. Oil pan gasket is sold seperate.

Another question, the camshaft button and spring. Does that come in to play on the 3800 engine? Is that easy to lose on removal and hard to install on reassembly? Thanks for your time and patience

It will stay within the bore of the cam. The VIN C was the last one to use it. The series I went to the thrust plate design. I could not find a replacement when I did mine so I reused the old one.