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Bridgeport-like idle on my fresh rebuild. Bad map?

Old Apr 25, 2007 | 08:46 PM
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Bridgeport-like idle on my fresh rebuild. Bad map?

Well I solved the issue of not getting any fuel or spark- it was the ECU. So I fired up the car and it idled like absolute crap. At first I thought it was a vacuum leak, so I took my intake manifold off, ripped the rats nest apart, and started looking for problems, but it wasn't vacuum related. The primary injectors were in the secondary spot and secondary injectors in the primary spot (I won't mention any names ) So I swapped them and problem solved, right? Wrong. I try to start the car and it just cranks and all I could notice was the smell of fuel. I tested the fuel pressure, and sure enough, there was a leak. Tore it all apart again, found a chunk of the o-ring had torn off, replaced it, put it all back. So I go to fire it up... nothing. Take off the plugs and I notice fuel pouring out of the housings, so I unflood it, change the spark plugs (3rd set on a motor with 2 miles on it ), and fired it up. It also shot out about 1/4 gallon of fuel out the exhaust

Alright, enough background information, let's fast-forward to where I'm at now with this car. So the car fires up fine now, but it idles like a bridge port. I went to test the vacuum with the car idling between 600-850 rpm and I got between 14-16 in-hg of vacuum. I started looking for intake leaks and found nothing. (Although I just read that having no pressure chamber could cause a drop in vacuum, and mine is currently disconnected, so that could be a minor problem) After that, I searched and found out that a bad map might be the reason for my bad idle, so I messed around with it and tried to simulate "normal" vacuum conditions with a Mity Vac (18 in-hg), and the car idled perfectly at 1000 rpm. So what does this mean? Does it mean I still have an intake leak and I need to seal it up so the car will idle right, or is the map bad? I've read that people have had their cars idling fine with 16 in-hg of vacuum, but why isn't mine idling right? Or am I looking in the wrong place? Thanks.

-Andrew
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Old Apr 25, 2007 | 09:00 PM
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I have no technical advice to give, but I wish you luck Does the oil pressure sender I sent out work properly?

Originally Posted by andrewdruiz
Well I solved the issue of not getting any fuel or spark- it was the ECU. So I fired up the car and it idled like absolute crap. At first I thought it was a vacuum leak, so I took my intake manifold off, ripped the rats nest apart, and started looking for problems, but it wasn't vacuum related. The primary injectors were in the secondary spot and secondary injectors in the primary spot (I won't mention any names ) So I swapped them and problem solved, right? Wrong. I try to start the car and it just cranks and all I could notice was the smell of fuel. I tested the fuel pressure, and sure enough, there was a leak. Tore it all apart again, found a chunk of the o-ring had torn off, replaced it, put it all back. So I go to fire it up... nothing. Take off the plugs and I notice fuel pouring out of the housings, so I unflood it, change the spark plugs (3rd set on a motor with 2 miles on it ), and fired it up. It also shot out about 1/4 gallon of fuel out the exhaust

Alright, enough background information, let's fast-forward to where I'm at now with this car. So the car fires up fine now, but it idles like a bridge port. I went to test the vacuum with the car idling between 600-850 rpm and I got between 14-16 in-hg of vacuum. I started looking for intake leaks and found nothing. (Although I just read that having no pressure chamber could cause a drop in vacuum, and mine is currently disconnected, so that could be a minor problem) After that, I searched and found out that a bad map might be the reason for my bad idle, so I messed around with it and tried to simulate "normal" vacuum conditions with a Mity Vac (18 in-hg), and the car idled perfectly at 1000 rpm. So what does this mean? Does it mean I still have an intake leak and I need to seal it up so the car will idle right, or is the map bad? I've read that people have had their cars idling fine with 16 in-hg of vacuum, but why isn't mine idling right? Or am I looking in the wrong place? Thanks.

-Andrew
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Old Apr 26, 2007 | 02:04 PM
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Originally Posted by mdpalmer
I have no technical advice to give, but I wish you luck Does the oil pressure sender I sent out work properly?
Thanks I installed the sender and it still doesn't work properly The gauge doesn't go up smoothly. I think it might be the gauge itself and not the sender.
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Old Apr 26, 2007 | 04:06 PM
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I think the problem is probably the map. What AFR and timing are you running at idle? My car likes about 12:1 afr and and around -5 to 0 lead timing.
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Old Apr 26, 2007 | 04:11 PM
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Originally Posted by point5chink
I think the problem is probably the map. What AFR and timing are you running at idle? My car likes about 12:1 afr and and around -5 to 0 lead timing.
IIRC, he's running a stock ECU.
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Old Apr 26, 2007 | 06:56 PM
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Originally Posted by point5chink
I think the problem is probably the map. What AFR and timing are you running at idle? My car likes about 12:1 afr and and around -5 to 0 lead timing.
My car only has these reliability mods: downpipe, vacuum lines, pd, rad hoses, and maybe a couple of other minor things that are negligible in this case.
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Old Apr 27, 2007 | 10:56 AM
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Anyone know where in the FSM I can find some testing procedures? I can't seem to find any.
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Old Apr 27, 2007 | 01:36 PM
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maybe i dont really want to know, but how did you manage to mix up the primary and secondary injectors anyhow. secondaries wont even fit in the primary rail right without some modification. I have no idea if the primaries will fit in the secondary rail though

Anyhow, how does it idle around 900rpm? Maybe you just have it set too low. 600rpm (your stated low) seems a bit too low for me. You said it idled fine at 1000rpm with the vac, but what abotu without the vac? Same thing?
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