For those that weren't following my previous threads:

Car is an '88 that was running very bad, chugging and backfiring, undriveable with a cold motor.

- fuel pressure was good
- all sensors seem to have the correct output
- new plugs
- old but serviceable cap / rotor (brass terminal)
- old but not arcing spark plug wires
- maf burn-off looked good

Disconnecting the maf made the car run almost perfect.

Pulled injectors and ran them on a bench. Two definitely had problems, four seemed marginal, and two looked good.

Tried installing Bosch III 22 lb (yellow) injectors. Car ran great when hot but was undriveable with cold motor. Finally built serial cable and scanned the car. Block learn at idle was maxed out.

Sent the stock injectors to be cleaned.

Put the stock injectors back in, took it out for a drive and in less than 1/4 the damn clutch went out. Just finished installing a new slave cylinder and took the car out .... FINALLY, the car is back to normal again!

Curt at www.advancedinjector.com cleaned / flowed the injectors. One injector was only flowing 60%! Now they're back within spec. He said it took quite a bit of cleaning to get that one injector back in shape.

I highly recommend them for getting your injectors worked on. Best price you'll find, very friendly, guarantees their work, and mine came out great!

 

I booked marked them. May send mine off this spring just to make sure they are in good order.

 

Very fast turn-around over the holiday as well!

Occurred to me today that I should scan it again. Now that its running good it will be nice to have a baseline measurement for future comparison!

 

Rob,

Thank you for the recommendation.
I'm happy we were able to resolve your C4's issues.

P.S. Reading through some of these posts makes me wish I had my 82 Collector Edition back.

Curt

 

Rob quick question for ya, assuming you don't have a lift how you did you get under the car for the slave cyl replacement? Ramps or jack stands? Mine is shot on my 89, not sure if i can get under the car yet.

My car had similar issues as you it was a bad ECM!

 

I use ramps and jack stands when I do one.

I use a jack to raise the car up and then put the ramps under the wheels(cars to low to drive up on them). Then I place a few jack stands strategically for safety Heck Ive been known to shove a tire under there just to feel a bit safer. I had a friend that ended up in a wheel chair from a jack failing while he was under his car. Its something that has stayed in my mind every time I work on a car since then.

 

I don't like working under cars, i think ill suck it up and pay the $350 to have it done. I always put the tire under the car, I did it this weekend when replacing the brake caliper on my DD and I had a jack stand and never went under the car, I try to be as safe as possible when the car is off the ground. I had a jack collapse once when I was taking the tire off and it scared the crap out of me.

 

I just jack up the drivers side of the car. Blocks / boards get placed under the tires and jack stands under the frame/suspension. Back in HS I had a car fall about 10 min after I got out from underneath. Ever since I double up on the protection. Should have seen how high I had my C5 up in the air to install long tube headers!! Jack it up, car down on a stack of blocks, put jack on blocks, jack it up and repeat.

One small bolt on the front end of the slave holds on the heat shield. Loosen the hydraulic line at the slave before removing the two mounting bolts. Swing the slave up into the engine compartment and swap it out. Fill the master cylinder, open the slave bleeder, push the slave piston to the bottom, close the bleeder and it will suck fluid from the master. Do that until no more air comes out of the slave bleeder. Drop the slave back down and it will hang at the correct angle to bleed the rest of the way. Only takes a couple of times to get the rest of the air out and bolt it back on. I like to put some grease on either end of the actuator rod.

Its a pain the first time. This was the second time for me and it was a piece of cake. It took longer to get the car jacked up than to do the swap. If you live near me I'd do it for less than $350!

 

Why clean Multecs or are they not Multecs?

 

I would say in my area, the is some, not a lot, some crud build up so the pattern I have established is every 3 years for anything that isn't daily driven. DD is every 100K. I send them off and don't use any snake oil in the gas

 

Nope, '88 didn't use Multecs.

 

Thought they were until mid 90 but if so, I would clean them every few years

 

They must have changed the hose between 86 & 88 then. I had mine done after buying it last year and there's a hard line from the master to the short piece of flex right before the slave. There's not enough slack to raise the slave on mine. I had a shop do it and they had a bear of a time getting all the air out of the line.

Here's a tip to try if you're in trouble like my mechanic was. He bled it several times but never got it all out. There a youtube on using a tip and line from a brake bleed kit that helped get some out but no all of the air out of it. I lucked out and work with a guy that used to be a GM mechanic and he gave me a tip that worked for me. After getting out all the air you can by bleeding, pump the clutch pedal several times (everything hooked up like it's supposed to be) and hold the pedal down for about 5 minutes. The idea is that the air will rise back to that gooseneck in the line over the master cylinder. At the end of 5 minutes let your foot slide off the clutch and let it pop back on it's own. The idea is that the rush of the hydraulic pressure coming back will push the air out of the line back into the master cylinder. I tried it and it did work for me so passing it along in case it might help someone.

I swear if my master or slave ever go bad again, I'm going to see if there's full ss flex line to replace that hard line so the slave can be lifted above the master to aid in bleeding the air out of it. I haven't seen one yet for an 86 but hopefully something can be found if that ever comes up again.

 

The flex hose isn't very long on the '88 either. It comes up a little above spark plug level.

 

It occurred to me, was your mechanic trying to bleed the slave with it bolted to the bell housing? It will be at the wrong angle. Need to do it with the bleeder pointing up.

 

No, screw the cap with a tube on and it forces fluid thru the lines. Open bleeder screw at brake caliper to start, close to stop when you are satisfied. Repeat.