84GN frustrations

[turbo84gn]

I originally got the car from my brother, (he owed me money, and I am still on the losing end of that deal!). It had sat for several years due to a blown transmission.

I overhauled the transmission three years ago. But no oil pressure. Taking apart the oil pump to pack it with vasoline I found very heavy grooves worn in the plate, which I machined flat and re-installed. Everything ran well, I was able to drive the car, so I thought "Great! Now to work on the interior."

As soon as I drop the seats off at the shop, the motor decides not to run anymore. So over the next couple of years (I am also working on remodeling the house, new kid, college at night, a Dad that insists that I work on his 87GN and his house instead of my projects!) so the diagnostic process takes a while to complete.

I kept getting plugs that shared a coil to foul (I later found out it was coincidence), even after replacing the coil pack, so figured it was the module itself. Upgraded to the module to the 87 version (84 replacement was expensive!). Still the same problem.

Close inspection showed many cracks in the headers, had them fixed.

After lots of reading I knew that it couldn't be the crank sensor, because it sort of wanted to run, so I started looking into the cam sensor as the culprit. New cam sensor and plugs (I have gone through several sets of plugs because of the fouling problem). Still no success.

Then Dad asks me "How old is that gas?" Pause from me as I think dumbly.

I then pump out about 5 gallons of very yellow varnish. Add 5 gallons of AGRI-Plus 90 (our local gas station has a pump that has a gasoline that has additives for lead replacement, detergents, stabil, anti-varnish, etc., etc., very good for older equipment or stuff that doesn't get used a lot) and new plugs, again. Now it tries to run if I feather it. Acts now like it is out of time. But I was very happy! This was an improvement over the last few years.

Removing the front cover showed the worst timing chain I ever saw. Beleive it or not, but all of the nylon was intact, but with deep grooves worn in it, as well as in the crank sprocket. The chain was so bad that when I "squeezed" it in the middle, they could darn near touch!

Timing chain installation is complete, but still doesn't want to run right (see previos postings for history of problem). I am certain that the timing chain is on right, I had my Dad and my brother double-check me. I have uploaded a saved turbo-link ECM file on my homepage at http://www.geocities.com/turbo84gn/cars/cars.html

I can get the car to run if I feather the gas at about 1400 rpm, but I get a steady backfire. If I let off the gas it will die. I'm ready to pull it next to the road and put a FREE sign on it.

Any suggestions and what to look at next?

Arthur Keene
turbo84gn@yahoo.com
84GN (all stock - maybe soon all scrap!)

 

[mark p. liner]

it sounds like two things, spark or fuel. it seems you have replaced most of the things that would cause bad spark, how about the wires? do you have enuf fuel pressure? have you put a fuel pressure guage on it and checked it? your problem really sounds more like fuel to me. i hope its something simple, good luck

 

[crazygn]

Belive me it will get better , ive had way to many problems with mine to list.

Do you have a fuel press gauge to see what your set at now. could be the fuel sock in the fuel tank . Have you pulled the valve covers to make sure the rockers are moveing mine did some thing like this when my cam and lifters died on me. I would say some thing in the fuel system , may be pull the tank if you get bord and check the pump and fuel sock out.

 

[REDS HOT AIR]

fuel sock is probly gummed up and the injectors could probly use replacement or atleast pulled and sent off for a real cleaning and flow test

 

[turbo84gn]

The car is stock, so I still have the 233 regulator. Pressure is solid at 30lbs. No leak down, even after an hour. As another troubleshooting step, I used injectors that just came out of my Dad's 87 which was running perfectly before they were removed (he upgraded to 42.5lb). When I pumped the old gas out, I had a very solid stream. Wires are new. It really sounds like it's out of time, and there seams to be excessive crank case pressure (smoke/fumes coming from breather). Maybe I will pull the covers and see what's moving in there (or not moving). I did do a pressure check. All were around 145lbs give or take 10.

 

[mycarsucks]

have you double checked to see if the cam sensor is installed correctly? They are really really easy to mess up and could cause the problems you describe.

 

[TurboToy]

things to check

have you tried a known goos mass air sensor? my 87 did the same problem and fouled the plugs too much fuel, and have you checked to see that the coil pack is on the right side? making #1 hit on wrong side. when i first bought my 84 these were the things i found wrong right off the bat.