Fluidplay

...should th ISV be completely air tight? My engine, thoughit running rich, won't hold idle and have been searching the RL archives for answers and came up with the ISV as a probable cause. I have a spare used one and plugged one side of it and blew in the other and it doesn't hold pressure. I'm assuming if it's part of the vacuum system it should. Correct? I'm chipping away at this problem....thanks for your help!!

Mikes3.0cabturbo

My ISV was working perfectly on the S2, it doesnt hold pressure when you blow through it, there is a slight leak through.
rgds
mike

Tom M'Guinn

They should not leak air, but most do when old. If you are running too rich to idle, a leaking ISV would only help (by letting more air in to mix with the extra fuel). What is happening with your car? Does it run well except at idle? How do you know it is too rich to idle?

F18Rep

There is a good discussion on troubleshooting the ISV over on Pelican - it was about 6 months ago. Bruce

Fluidplay

Yeah... I know their separate issues, but thought the idle situation could be a ISV problem. In regards to running rich, Tom - I have a WB hooked up. If I keep the revs up it will bring the A/F up for a moment, but drops right back down to 10:1. Same thing when i've driven around briefly going thru the gears it seems to come up in range and as I let off it goes lean for a second then drops back down to 10:1 I'm trying to figure out this Power Perfect fuel controller...having some issues with the software program.

bigdeano

Get on pelican and lookup posts by a guy named soxnail, he's an ISV guru and helped me through my ISV problem. I even sent mine to him for him to rebuild for me but the magnet inside ended up being busted so there was nothing he could do about it.

Fluidplay

Thanks...i'll take a look.

blodstrupmoen

I had a leaking ISV , replaced it with a new also leaking ISV .. Now I have exchanged the ISV 3 times and all are leaking a little.

The DareDevil

I pressure tested my system and the only part that was leaking was the ISV (inner seals I think). From what most people say, even the new ones are 100% air tight.

I used to run without one, so I think I'll go that route again.

Tom M'Guinn

Oh, I see... some a/f gauges don't actually show below 10:1, so you might be running even richer than that. I've found that the car will start to bog just richer than 10:1. How is your car set up? Sounds like you have some fundemental issues to tackle before fine-tuning -- wrong fuel pressure, chips not mapped for the MAF or injectors or something similar. If this just started happening out of the blue, I'd check the fuel pressure regulator first (to make sure it is giving the right fuel pressure and not leaking fuel into the vacuum tube).

Ian Carr

I just took out the ISV, you gotta give it a little gas to keep it idling when cold, in the cold. Other than that car idles just fine.

The DareDevil

You can turn up the idle just a tad to help with cold starts. I believe the turbos are supposed to idle at around 840 +/- 40rpm.

Fluidplay

Tom - I have a FP gauge on the rail and running about 39.5lbs. I thought it might of been a chip issue and Lindsey sent me anouther one at no charge to see if that was the problem...no change. I'm afraid it could be in the wiring since I "butchered" it up when i re-covered it with new fire-sleeving. It gets good continutiy on all asssociated point runs, but I'm wondering if there's an impedence problem due to the splices?? Current injectors are new Siemen's 55# and just to see if it would make any difference I installed the stock injectors (which were just re-serviced by Witch Hunter) and no change. To be honest...I really need to find someone locallly here who knows this stuff. I know enough to get myself in trouble...

Tom M'Guinn

From your other thread, I understand this is a new engine with new LR MAF, chips, sensors, injectors, etc. Sounds to me like you have something off-base on the basic set up -- i.e., chips mapped for different injectors, bad map in the pp, etc. Have you tried pulling fuel out via the power perfect? I've not used that system, but sounds like the thing to do, no? Where is RSM?

Fluidplay

Yep...everything is new and the more I mess with it trying to figure it out, the more concerned I am screwing it up! All components & chips were matched from Lindsey, so I was hoping this would go MUCH easier after the rebuild. What do you mean by "pulling the fuel out" via PP (bypassing the PP)?
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