Pfc. Parts

Hello all -

I've completed an intake refresh on my '85 auto US. The car starts and runs with a little effort, but it doesn't run right yet. Prior to performing the intake refresh I did a timing belt replacement/refresh last year.

The initial symptoms (2011) were:

1) Wouldn't start with simple turn of the key. Throttle had to be "feathered" to get it running then "babied" for a while until the engine warmed up. Once it was warm it ran rough at idle (around 700 rpm). Drivable but not as fun as she once was.

Since the car only had 60,000 miles on it and had been in storage for over 10 years I decided to replace the belts before trying to get it working better. I have a rational fear of timing belt failures on this engine and didn't want to make anything worse.

After the Timing Belt Refresh there was no change in engine performance. At this point I began trying to figure out what was wrong.

I started with an intake refresh which was recently completed (this morning). A large vacuum leak was found ( 928 110 602 00 ) and corrected. During this procedure all the vacuum lines were replaced along with the ISV. The Throttle Position Sensor was not replaced. A vacuum test was performed using positive pressure at the MAF per Dwayne's procedures and tooling. The sealed intake held 1 to 1.5 lbs positive for 5 seconds. Pressure above 1.5 caused the test apparatus to blow off the MAF. I considered this a positive test result; the intake was sealed.

Following the refresh there were two electrical problems identified and corrected:

1) The temperature switch controlling the auxiliary fan was defective. After reconnecting the battery the fan came on in a cold engine. This part ( 928 606 217 00 ) was replaced.

2) The battery had failed and was replaced.

Some possibly important notes:

1) The MAF was set to 380 ohms (factory default reported by PorKen?) on re-installation.

2) The timing belt was installed using cam and cam cover mount marks made by the factory. No precision cam timing was performed during that refresh.

3) All ignition components were replaced; coils, distributors, ignition wires and spark plugs.

4) Fuel injectors were re-furbished with new seals but were not metered, re-built or replaced.

I consider the intake refresh complete and successful at this point, however the car still runs like crap. The symptoms have changed though. At present they are:

1) Engine will not start with a simple turn of the key. The throttle must be feathered to get it running.

2) Once running, the throttle can be released. The idle will dip sharply then recover to about 700 rpm. (this is a mild improvement).

3) The engine idles laboriously. It sounds like it isn't firing on all 8. The car rocks noticeably at idle.

4) The engine smooths from 1000 to 2000 rpm, roughens again at 2000, then runs smoothly to redline.

5) Suddenly releasing the throttle above 1000 rpm causes the engine to stall.

All of that said, I welcome further questions that might reveal where the problem is along with suggestions on where to focus attention.

Best regards to all, thanks in advance for any help,

PorKen

Using a 7mm socket, turn the idle speed screw at the front on the throttle body CCW one full turn to raise base idle speed until it idles better.


Double/triple check the spark plug wire routing.

joejoe

Fuel pressure, dampner,regulator good?

Pfc. Parts

I don't understand how I might turn a screw on the throttle body with the engine running without removing the intake manifold. Running the engine without the manifold would be dangerous? No filter, no plenums? Is this OK?

How does this work?

I'll double and triple check the plug wires.

PorKen

Idle speed air bypass/bleed screw - not a mounting bolt.

Base idle speed is set with this screw which allows air to bypass the throttle plate.
The idle control valve requires the base idle to be set properly.

There is more to setting the base idle, but for now, just back out the screw so you have a decent idle.

Screw is above the red caps in pic below.

Mrmerlin

in the picture the air filter is upside down.
the coil wires should be checked for rubbing on any metal part and the ends should be clean
Do a firefly test, open the hood remove the air tubes then run the car in the dark looking for ignition sparks from the wires

PorKen

Airbox intake tubes are the wrong part #s. ('85-'86 are special/NLA.)

Hood shocks are upside down.

Jump post cover missing.

(Fender brace not yet installed, I assume.)

Pfc. Parts

Is this adjustment made with the intake manifold in place or with it removed? In other words, do I use something like the MAF adjustment tool to work through the manifold or should I remove it?

Thanks,

Pfc. Parts

Sigh. The new one doesn't have the "Top Oben" marks on it. I had a 50/50 chance.

You know the 50/50/80 rule right? If you have a 50/50 chance, you'll get it wrong 80% of the time?

Pfc. Parts

OK. Enough already. I happen to like the hood shocks upside down. NLA? Only if you aren't willing to use the wrong part. Fender brace? You want to live forever?

Jump post covers are for people who have perpetual batteries.



PS: The cover really is there, It's just hanging out of sight because I only took the trickle charger off for the picture.

Pfc. Parts

On a more serious note, you wouldn't have a lead on the correct air tubes would you? I was on a waiting list for about a year, no joy. I ordered these (87-90 something) because "they might work". They don't, as you can see. I'm planning to do some creative cutting and splicing to see how close I can get.

I still have the originals but they're a little beat up. I'd love to find someone making the right ones. I need one of those 3D printers Jay Leno has.

Pfc. Parts

You two are concourse judges aren't you? Don't try to hide it!

The coil wires got scrubbed down pretty well when the coils were replaced, *but* I have a problem on the drivers side coil; the screw that threads into the clamp holding the coil to the chassis is partly stripped and won't take more than moderate tension. I haven't figured out how to fix this but the coil is tight presently and doesn't *seem* to be a problem. I'm thinking I'll either try to replace the holding clip, which could be a major operation, or get a larger self-tapping screw to replace the bolt that's stripped it. Thoughts?

I did something like that, spraying a water mist in the air over the engine in the dark. Nothing jumped out.

PorKen

AFAIK, hood shocks go bad quickly if they are pointing the wrong direction most of the time.

Note the black driver handle, connected to a 7mm socket on an extension.

Pfc. Parts

BTW Ken ? I admit to a transparent troll by mentioning your screen name in the problem description. I relied heavily on your MAF tuning write up and tools before deciding on the complete intake refresh. If it hadn't been for your work I would not have found the vacuum leak that was plaguing me.

On a similar note, I'm wondering if this car needs precision cam timing and seriously considering your bump stick. The car's cam timing might be off, would these symptoms indicate that? If so let me know. It wouldn't be a casual investment but I have two of these cars and one is destined for the track. I expect I'd get good use of the tool if it would help me in my current situation since I'm almost certain it will help me in the next.

Regards,

Pfc. Parts

Thanks. They've been in all of a month and I've never closed the hood. I'll reverse them tomorrow!

Excellent! Thank you!

After this I'd like to talk to you more about cam timing.

Best Regards,