Regulator or FP

[c4ever]

Recently the 85 has had to crank for some time before starting. Ususally after initial start up in the morning. This car has always started at the touch of the key in any condition. I metered the fuel rail and upon turning ign on I get 40psi which goes right down to 0. Does not hold pressure at all. The car will start and idle at around 25psi and jump to about 30 psi when reved. Is this more indicative of a regulator or pump. I tried to pinch return line but for the life of me there is no access to flex hose. If there is they did a da*n good job of hiding it. Car idles and runs fine even at wide open throttle.



;help ;help

Carlo
;stupid

 

[rrubel]

From the replies I received when I asked a similar question, it's more indicative of a leaking injector (most people said the cold-start one). I can't see the fuel pressure regulator being the problem - it's just a spring and a metal plate. Pressure would be held by the fuel pump (which was also fingered as a less-likely culprit) at one end and the injectors at the other.
[RICHR]

 

[c4ever]

OK finally got to return line and pinched off. Pressure holds at 60psi+ so it's off for a high performance regulator. I may see if TPIS has one for 85.

This is why I always keep my weekends open

Carlo

 

[rrubel]

Got mine (for 86) from TPIS. Included new gaskets for the plenum as well... It's an easy install, except for getting the plenum off - there are little plastic tabs attached to the gasket that hold it in place on both the runners and the plenum and you either need to loosen the runners at the bottom or really whack the plenum to break them. I took a block of wood, put it on the plenum, and smacked it around with a hammer until they broke. I think all told the project took me about two hours.
[RICHR]

 

[c4ever]

Thanks for the input Rich. I've never taken the runners off so every little bit helps. Hopefully it's an uneventful install. I bought a high perf. unit from Ecklers. It'll be interesting to see if I get a performance increase as the old unit wasn't really holding pressure at all.

Carlo

 

[rrubel]

What is the psi of the new unit, or is it adjustable? I found that my stock one was holding about 35 at idle, which is within low norm for my year. However, all the magazines say that 42-43 is better, so I bought an adjustable one and set it for that. Does it give more power? Dunno...I think I need to play with it a bit and work out the exact pressure that's right for my car. At one point I had it WAY too high and the injectors were loudly complaining.

BTW - if it's the disc or spring inside that's causing the problem, you may be in for a rude awakening when your hi-perf one arrives. Mine turned out to be just a shell that replaced the stock (non-adjustable) one but it still used the same spring and disc. However, instead of a bump-out on the inside of the shell that pushed the spring a certain amount, there was a hole and screw to turn to increase or decrease spring pressure. Hopefully yours is an entire unit and not just the shell...

Also, does yours come with the torx bit to remove the old one? It's a weird piece - I think a T10 with a hole in the middle because the stock bolts are "tamperproof" and have a piece sticking up in the center of the area for the bit (mind blanked - can't remember what it's called!).

[RICHR]

 

[c4ever]

It's a complete unit not a rebuild and is adjustable. I don't know if it will come with the bit but it says it includes ALL parts for the installation. Something tells me I'll be buying a torx bit. I'll take a look my unit. Is the bit a common part Sears, Pep Boys, etc? I've got some nice torx sets but don't think they will work on a tamper proof bolt.:confused


Thanks for the heads up Rich

Carlo

 

[rrubel]

The bit for mine came with the regulator, so I've never had to look for it anywhere. If you do need it, I'd be happy to send you mine, or you might have luck at your local Fastenal dealer (they seem to have all the oddball bits and sockets I've ever needed).
[RICHR]

 

[Eagle85C4]

It is a security torx bit. If you get a good stout pair of pliars you can break the tip inside the bolt off and use a regular torx bit. In some instances I have used a drill to drill the tip out.

 

[Vettelt193]

What is the psi of the new unit, or is it adjustable? I found that my stock one was holding about 35 at idle, which is within low norm for my year. However, all the magazines say that 42-43 is better, so I bought an adjustable one and set it for that. Does it give more power? Dunno...I think I need to play with it a bit and work out the exact pressure that's right for my car. At one point I had it WAY too high and the injectors were loudly complaining.

[RICHR]

Your fuel pressure should be adjusted by air/fuel ratio, and not PSI... basically, it doesn't matter what the PSI is, only that your car has the correct mixture of fuel and air.... when adjusting your regulator: The computer compensates for too much or too little pressure by changing injector pulse. basically, if the pressure is too high, it will shorten the pulse; too low, lengthen the pulse. You really want the pulse to be normal becuase too short or too long of a pulse leads to bad spray, which leads to a bad burn and less power... to make a long story short, you have to reset the computer between adjustments, so the pulse goes back to neutral

 

[rrubel]

Sounds reasonable... other than disconnecting the battery, is there a way to do this?
[RICHR]

 

[Vettelt193]

i think for the home mechanic, the battery is the way to go