Unable locate a vacuum leak, HELP DA NUBI

[jesspross]

I've got a '92 FJ80 with about 156K miles on it and is my daily driver (when it runs) I've replaced ALL of the parts assoc. with the cooling system (new Rad., new W/P,thermostat,belts,fan clutch, idler pulleys and so on and so on)

I have also replaced ever component in the exhaust sytem except the manifold ( new EGR valve, new converters, crossover pipe, muffler-flowmaster and a new tail pipe) in an attempt to get my truck to pass the emissions test and finally found a guy to get it to "pass".

I have been driving around with a sloppy brake pedal for a few weeks after I rebuilt the front axle to replace the seal between the diff. and the Bir. and while I had it all opened up I thought it would be a good time to replace some of the stuff in the front axle ( new birfields, bearings, seals, calipers, rotors and hoses)

Well I thought that I just needed to bleed the brakes again, did that and still had a sloppy brake pedal...so I replaced the master clynder and then the problem got really weird, I was amazed with how hard the pedal was now, so just thinking that I got a bad unit I pulled it and replaced and had the same issue with the new M/C.

Then I started to think it was my M/C powerbooster, went and got a new and put it on and still had a hard pedal .

Well then I had the great idea to take it to a professional shop and let them figure it out, they said the parts that I had put on were **** and replaced them with Mr. Toyota parts and the problem was still around, so they are looking at my truck to dertimine the cause of the low vacuum.


They've checked the timing, adjusted the valves,replaced all of the vacuum hoses, blown out the vacuum hose connections but still no luck with the vacuum leak.

The motor doesn't leak any oil so the leads my to rule out any type of air being sucked in via PCV and the hoses from the air flow meter are in good shape without any major cracks.

I'n statrting to think that the EGR modulator my have gone south on me and that is where my leak is coming from.


If anybody has ANY ideas I will gladly give them A shot as the guy at the shop is as confused as I am and has put about 13-15 hours into trying to figure out thie problem without much luck, good thing for me he's not charging me to figure it out!!!


Thanks in advance for your time and attention in this matter.

Jess

 

[Grench]

Does the cruise control work? It has a stealthy vac line that runs back over the engine to it. It came unplugged on the '92 we used to have and it exhibited low vac issues.

IMHO YMMV

 

[jesspross]

I don't know if that has been checked yet...guess I know what I'm doing on Sat.

Thanks for the info., I'll check back soon to let you know how it goes.


Jess

 

[jonheld]

Does the cruise control work? It has a stealthy vac line that runs back over the engine to it.

What? There is no vacuum line to the CC module on a 91 US spec FJ80. I had mine out yesterday as a matter of fact (trying to figure out why it stopped working). There is 1 electrical connector and 2 cables, 3 12mm bolts.

 

[jonheld]

http://gclcny.com/jh/images/Strife/3FE TuneUp.pdf

Have a look at #7,8,10,11,12,13

Also check the gasket on the oil fill cap and the gasket on the oil dipstick.

 

[Trailbus]

Try the starting fluid method for finding vacuum leaks. Park outside in a well ventilated area and lightly spray around the vacuum hoses one by one while the engine is running. The RPMs will jump up when you hit the leak (if you have one).

Just stay away from the spark plug wires because it will also let you know if you have arcing wires.

 

[LC80Ducati996]

I use a propane torch. The type that has a propane and an oxygen tank with the torch on the end of the hose. No need for a oxy tank for this test. In fact dont even have one hooked on it. Just trickle a dribble of propane out the end of the torch. Dont light it DUH... You can run the torch across lines and connections. When you are right on a leak it will get sucked in by the vaccum and the engine will idle a touch faster. Works good for me and no starting fluid all over. Use an open area of course and a low trickle of propane and it is safe.

 

[jesspross]

Thanks for all of the great ideas, I will be working on the truck this weekend and will post an update.

Jess

 

[jesspross]

I checked the FSM and followed the hose routing, and OF COURSE a few hoses were transposed and the EGR Modulator wasn't working...now it feels like well,.... it fells like it could keep up with the rest of the traffic on the freeway.

Althought it has (has had) a problem going into OD too early, about 50-53 MPH, really strange.


anyhelp on the tranny stuff would be great.

Thanks,

Jess

 

[jonheld]

Are you referring to the tourque converter locking up? That should happen at 45 MPH.

Remember it's a 4 speed tranny with tourque converter lock up. There is no "OD".