One step forward, 2 back!

[Aquabrit]

Hi guys i am frustrated, tired and in need of advice. I have been doing alot of work on the mark recently ready for inspection but i think im cursed! I did a coil conversion, new upper and lowers, strut rod bushes and fixed other troubles along the way. (2 broken wheel studs for one) Anyway i got it finished and started the car. Now it wont idle properly and revs up and down like a maniac. I have checked for vacuum leaks etc but no luck. Is it likely IAC trouble or have i disturbed something? Also, the brakes now barely work. The calipers are not seized, fluid is ok etc. The pedal is firm and the vacuum pipe that connects to the booster is working. Do you reckon i have disturbed something when pulling the m/cyl away from the booster to do the upper arm? Im really annoyed cos i worked all weekend, everything was fine and now its not. Any help appreciated. Martin.

 

[Frogman]

Hmmm...

I find it highly coincidental that your IAC would give out at the same time you did a conversion. And since i don't believe in coincidence....


You may have disturbed some of the emissions stuff. Make sure all the little emissions related vacuum hoses are properly connected under the driver's side strut tower cover. Check the driver's side engine area carefully, you might have unplugged something there.


Did you disconnect the brake lines from the Master Cylinder when you removed it? If you did, you'll have to bleed the brakes, as surely, air might be trapped in them. Ah. I see the pedal is firm, so that's not an indication of air in the system.

Did you reconnect the brake fluid pressure sensor?

Brake booster check valve maybe?

To test the function of the power brake booster check valve:

* Start and run the engine for at least 10 seconds.
* Operate the brake pedal to check for power assist.
* Disconnect the vacuum booster hose from the power brake booster. Do not remove the power brake booster check valve from the power brake booster.
* There should be enough vacuum retained in the power brake booster for at least one more power-assisted brake operation.

1. Check the hydraulic brake system for leaks or insufficient fluid.
2. With the transmission in NEUTRAL, stop the engine and apply the parking brake control. Apply the brake pedal several times to exhaust all vacuum in the system.
3. Apply the brake pedal and hold it in the applied position. Start the engine. If the vacuum system is operating, the brake pedal will tend to move downward under constant foot pressure. If no motion is felt, the power brake booster system is not functioning. Continue the test with the following steps.
4. Remove the vacuum booster hose from the check valve connection. Manifold vacuum must be available at the check valve end of the vacuum booster hose with the engine at idle speed and the transmission in NEUTRAL. If the manifold vacuum is available to the power brake booster, connect the vacuum booster hose to the power brake booster check valve and repeat Steps 2 and 3 above.
5. Check and if no downward movement of the brake pedal is felt, replace the power brake booster.
6. Operate the engine a minimum of 10 seconds at fast idle. Stop the engine, and let the vehicle stand for 10 minutes. Then apply the brake pedal with approximately 89 N (20 lbs.) of force. The brake pedal feel should be the same as that noted with the engine operating. If the brake pedal feels hard (no power assist), replace the check valve and retest. If the brake pedal feels spongy, bleed the hydraulic system to remove air.

How much vacuum is the motor pull ing? I'm sure you may not have a vacuum gauge, but it never hurts to ask.



Are you getting any CEL's?

 

[Aquabrit]

Hi frogman! No CELs. I checked those little tiny vacuum pipes and they seemed ok. I sprayed some carb cleaner around to see if i could find a leak but nothing. Ref brake m/cyl no i didnt disconnect the pipes just pulled it away carefully so i wouldnt kink them. I havent bled the system yet but i didnt see the need as i hadnt opened the system and the pedal is firm. Yes it does seem like too much of a coincidence doesnt it? lol. Maybe im being punished for choosing coil over air...

 

[Aquabrit]

Oh vacuum? no idea. Thanks for your advice so far will give those things a try first!

 

[Frogman]

I'm sure you double checked to make sure you hadn't kinked the steel lines, yes?


Unplug the IAC and see if the engine RPMs stabilize.

 

[Aquabrit]

Yes the lines seem ok. I took the front calipers back off and the pistons move ok so fluid is getting down there. Even if the brake booster isnt working i would have thought i could still stop the car with real hard pushes but i dunno now. Is the IAC by the throttle body on gen 1? Could try disconnecting it, cleaning it etc.

 

[Frogman]

Yes, the IAC is all the way at the back of the intake manifold, on the TB. I hear they are a joy to pull off and clean/replace.

As far as the brakes... I don't know what else to suggest. It almost sounds like an obstruction in the lines. The ABS pump should be OK, especially since you didn't drain the brake system. (Something you don't really want to do unless you have Dealer scanners like an NGS Tester).

 

[Aquabrit]

Guess i will go back to it and re-check everything again and do the stuff u suggested. Whats the fluid pressure sensor? I reconnected the plug that goes to the reservoir cap but i assumed that was a level sensor.

 

[Frogman]

Yes, that's the brake fluid level sensor. There is a brake pressure warning switch, but damn it, I can't find it. I thought it was around the master cyl, but I'm not seeing it in any of the pics I took when I pulled the engine out of my 98, so I'm assuming its arund the ABS pump.

 

[JMiles_T]

One possibility: On the brake booster, the plastic piece where the hose plugs in can be removed. It's possible for it to leak if it isn't sitting right, or if the rubber has worn. When you start your car, listen for air from that area.

Hi guys i am frustrated, tired and in need of advice. I have been doing alot of work on the mark recently ready for inspection but i think im cursed! I did a coil conversion, new upper and lowers, strut rod bushes and fixed other troubles along the way...

Aside from the studs, what other troubles did you go after? Your answer could have relevance to the current problem.

 

[Frogman]

Plastic piece is the check valve.

 

[Aquabrit]

No i checked that and its ok. No hiss or anything. Will have another look at it soon when my eyes are fresh and im motivated again! lol. No the other troubles were related to the suspension change. (Strut rod bushes seized to shaft, lower b/js not loosening, just spinning etc.) Frogman talked of brake booster trouble or line blockages so will check those out in more detail. Thanks.

 

[Aquabrit]

Thanks frogman. Will check the function of the check valve etc. Will be working on car again in a couple of days so will post what i find then.

 

[billcu]

The idle problem could be a vacuum leak also.

If you don't find any vacuum leaks and suspect the IAC valve, try disconnecting the battery for a while then reconnect it. This worked for my idle problem.

 

[Aquabrit]

Hi billcu. The symptom doesnt suggest a vacuum leak. On warm up its fine then it revs up and down between 500 and 900rpm rapidly then settles for a few seconds, then does it again. I tried disconnecting battery for 20 mins but made no difference. How long should i keep the batt disconnected? Thanks.

 

[billcu]

I would think that 20 mins would be enough. Oh well, it was worth a try.

I read once where someone actually connected the positive and negative cables together while they were disconnected from the battery. I didn't do this and I'm not sure what difference it would make.

 

[Aquabrit]

Thanks anyway. I could try disconnecting it for alot longer i suppose, just incase. Touching cables together huh? Cant see what that would do unless it helps clear the keep alive memory? No idea. I really need to invest in a decent workshop manual for these cars as im in unfamiliar territory!

 

[Frogman]

Search LvC. there's a link to a website wher you can download the manual on CD.

 

[Aquabrit]

Really? cool thanks frogman will do that. I got a chilton but its crap!

 

[neodon]

93 there is a rubber seal where the master meets the booster check and see if it in there just a thought mines a 97 dont know if yours has one

 

[Aquabrit]

Ok thanks neodon. Cant hurt to go back over everything and look.

 

[Aquabrit]

UPDATE: Brakes better, but still no good. Heres what happened: I re inspected the lines and thought they might be kinked where they run by the wheel arch, under the fusebox. so i did some unkinking but it didnt help. i then pressed the brake hard and observed the brake m/cyl at same time (haha awkward!) and guess what? The inner stud of the booster had strippes a few threads and the cylinder was twisting and causing an air leak on hard application. Fixed that with some washers and the brakes are better but still not very good. (prolly cos i did more harm than good on the lines) Anyway, will take it into a garage to get the wheel alignment done and those lines replaced soon. The idle problem? Re investigated it, found nothing, disconnected batt for couple of hours, made no difference. Didnt try disconnecting iac yet as engine was hot and the car doesnt hunt until warm. However, i observed something which may be a clue to the hunt. When i turn the a/c on or other accessories to load the engine, the hunting stops completely! As soon as i turn them off it starts again. Reckon its the iac? I hope it is cos i can take it off and give it a good clean up! Now my stereo has started popping and playing up! lol. oh... the drama. Still, keeps me busy...