When coming to a stop I put my foot on the clutch and foot off the accelerator, the rev's drop to 200/300. most of the time the engine recovers and ticks over nomally, however on two occasions the engine has stalled. the AIC Vv has been cleaned. any ideas
Rev's dippin
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Hi, Gelcoat. Good to see you here again. Thought you'd left us.
Not too sure about the non-turbo, but on the turbos, there are various things that can cause this and it usually comes down to a leak in the induction system or the AIC valve. Since the valve has been cleaned to no effect, I'd guess there is a leak somewhere between the air mass meter and the engine but I'm not familiar enough with the non-turbo layout to be more specific.
Alternatively, if you're getting poor MPG, there's the possibility of a faulty air mass meter.
Not too sure about the non-turbo, but on the turbos, there are various things that can cause this and it usually comes down to a leak in the induction system or the AIC valve. Since the valve has been cleaned to no effect, I'd guess there is a leak somewhere between the air mass meter and the engine but I'm not familiar enough with the non-turbo layout to be more specific.
Alternatively, if you're getting poor MPG, there's the possibility of a faulty air mass meter.
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234 Posts
Hi,
Strangely enough, I have been encountering a similar problem. Whenever I come down from higher revs to stop, e.g. at traffic lights, juctions, etc, the idle speed fluctuates between 300-600 rpm, often threatening to stall. Cleaned IAC, per Bill's very informative site, and replaced all hose lines with silicone from Elk.
Any other ideas (auto choke, throttle position sensor, etc). Also getting worse MPG than usual.
Cheers,
Pete
Strangely enough, I have been encountering a similar problem. Whenever I come down from higher revs to stop, e.g. at traffic lights, juctions, etc, the idle speed fluctuates between 300-600 rpm, often threatening to stall. Cleaned IAC, per Bill's very informative site, and replaced all hose lines with silicone from Elk.
Any other ideas (auto choke, throttle position sensor, etc). Also getting worse MPG than usual.
Cheers,
Pete
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129 Posts
I think I may have a solution...
I had the exact same problem with my 90 non-turbo 2.3 auto. I cleaned the throttle body, intakes, injectors, IAC, (even replaced the idle valve), checked for vacuum leaks, but nothing seemed to cure the "dipping revs". Then, I considered the air mass meter. I took mine out, and sprayed a liberal amount of intake cleaner (some people call it carb cleaner, but it's specially formulated for injected engines), then let all the gunk come out, dry, and then I put it back in. Ever since, it's been running like a swiss watch.
Let me know how it goes!
I had the exact same problem with my 90 non-turbo 2.3 auto. I cleaned the throttle body, intakes, injectors, IAC, (even replaced the idle valve), checked for vacuum leaks, but nothing seemed to cure the "dipping revs". Then, I considered the air mass meter. I took mine out, and sprayed a liberal amount of intake cleaner (some people call it carb cleaner, but it's specially formulated for injected engines), then let all the gunk come out, dry, and then I put it back in. Ever since, it's been running like a swiss watch.
Let me know how it goes!
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129 Posts
Ok, I was driving my car again tonight, and unfortunately, I encountered the "rev dip" again. It ran so beautifully today, with absolutely no problems whatsoever, but this evening, the revs bounced around a bit. That being said, it wasn't nearly as bad as before I cleaned the air mass meter, since now the revs only drop down to about 500 rpm, and go up to about 1000 rpm. My engine is in no danger of stalling, which is good, but I'm still a little disappointed that it's not running the way it should be. So, tomorrow morning, I'm going to clean the air mass meter again, as well as the throttle body, and see what else I can adjust to make it better... It's strange, but it seems to get a little better every time I tinker with the car... At this rate, it'll be fixed in about a year!
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1,359 Posts
Best to check the hoses on the iac are clear as one of the hoses going to the valve was dirty to, also check all the hoses for leaks and that they are tight.
Take all the connectors of the any parts like the iac,cold start inj ect spray some wd40 in and work the connections just to make sure they are not gummed up, as on my cse this was the problem as after doing this it idled spot on.
Check the pull out valve with the hoses on that comes out of the cam cover as this had shrunk was loose and i think it is linked into the iac and was not giving the iac the right pressure, so i wound some ptfe tape round it to make a good fit again, the idle has been spot on since.
Take all the connectors of the any parts like the iac,cold start inj ect spray some wd40 in and work the connections just to make sure they are not gummed up, as on my cse this was the problem as after doing this it idled spot on.
Check the pull out valve with the hoses on that comes out of the cam cover as this had shrunk was loose and i think it is linked into the iac and was not giving the iac the right pressure, so i wound some ptfe tape round it to make a good fit again, the idle has been spot on since.
A lot of these grommits can be had from a dealer for pence (or a pound or two). On my '91, I replaced the one you are talking about Microcat, the PCV hose grommit, which had totally disintegrated.
I also did the two or three rubber ones in the inlet manifold. Actually, they started blowing out under boost, but it was cheap enough that it would be worth doing on an older car anyway.
I also did the two or three rubber ones in the inlet manifold. Actually, they started blowing out under boost, but it was cheap enough that it would be worth doing on an older car anyway.
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