Won't idle after a short drive

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Merkurstein
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Won't idle after a short drive

Post by Merkurstein » Tue May 14, 2019 7:15 pm

Car starts fine but can smell gas on start up and idles a lil high. I just tap the pedal and it idles down but it seems like the issue doesn't happen til after I drive down the road. Just a trip around the block and when I push the clutch in the rpms drop way down at idle, it will run up and down (say like 400 to 600) until it completely quits which just takes a few seconds. Then it will start right back and run fine until I take it down the road.

So far I have checked the fpr it holds a solid 25psi. checked the vam and seems to be doing right, looked over the vacuum lines and can't find anything.

This issue didn't happen until I went from my repinned la3(stopped working) and big vam to a pf3 and small vam. The car is a 87 , would the pf3 make a difference sensor wise, TPS, IAC,O2? I also have a Pf2 I could put in it.

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Re: Won't idle after a short drive

Post by John Brennan » Wed May 15, 2019 8:43 am

Re-pinned LA3 shouldn't pose any wiring changes when going back to a PF3/Small VAM. The only thing that changes is static timing, which goes from 10* BTDC to 13* BTDC, SPOUT disconnected. Have you done that, and checked all your other settings (TPS, cam)?
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andyofcolumbusmerkur
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Re: Won't idle after a short drive

Post by andyofcolumbusmerkur » Fri May 17, 2019 10:15 am

Did you do the full tune up procedure including spraying carb cleaner through the iacv until the run-off is clear?
You can barbecue it, boil it, broil it, bake it, saute it. There's shrimp kabobs, shrimp creole, shrimp gumbo, pan fried, deep fried, stir fried, pineapple shrimp, lemon shrimp, coconut shrimp, pepper shrimp, shrimp soup, shrimp stew, shrimp salad, shrimp in potatoes, shrimp burger, shrimp sandwich....

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Merkurstein
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Re: Won't idle after a short drive

Post by Merkurstein » Sat May 18, 2019 5:45 pm

Yes timing is correct and engine has a complete fresh tune up. Changed computers and it fixed the issue. Put the PF3 in it and ran fine today, so far lol. Both EEC are from parts cars. Idle is still a little high but better than it quiting. Thanks for the recommendations

Sorry I said pf3 in my original post, it was the pf2

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Re: Won't idle after a short drive

Post by my8950 » Sun May 19, 2019 9:16 pm

Merkurstein wrote:
Tue May 14, 2019 7:15 pm
So far I have checked the fpr it holds a solid 25psi. checked the vam and seems to be doing right, looked over the vacuum lines and can't find anything.
Not saying this is the issue, but 25psi is way too low.
Pull vacuum line off when idling, set fuel pressure to 38-42psi, put vacuum line back on.
If you can monitor fuel pressure, you should see it go down a little as vacuum increases, and go up if/when you get into boost. 1:1 ratio, 1 psi fuel pressure to 1 psi manifold pressure.

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Re: Won't idle after a short drive

Post by Merkurstein » Sun May 19, 2019 10:27 pm

my8950 wrote:
Sun May 19, 2019 9:16 pm
Merkurstein wrote:
Tue May 14, 2019 7:15 pm
So far I have checked the fpr it holds a solid 25psi. checked the vam and seems to be doing right, looked over the vacuum lines and can't find anything.
Not saying this is the issue, but 25psi is way too low.
Pull vacuum line off when idling, set fuel pressure to 38-42psi, put vacuum line back on.
If you can monitor fuel pressure, you should see it go down a little as vacuum increases, and go up if/when you get into boost. 1:1 ratio, 1 psi fuel pressure to 1 psi manifold pressure.
I meant the fuel pressure regulator holds 25psi on a vacuum pump. The actual fuel pressure stays around 38 to 40. The car now just has a dead miss here and there, which a lot of XRs do from what I have read. The idle is still high even if I bottom out the screw, around 1100 to 1200 at temperature. I got some vacuum lines that has been needing to be replaced for a long time. Gonna check the IAC sensor and others too.

Starting body work soon as well, car is debaged , no rear wing, and no side cladding. Gonna patch a spot at the lower quarter on the drivers side and fill the pop rivet holes. I personally like the bare look more, plus everything being so brittle. Then going with a flat black. Owned the XR for over 15 years now and has went from transformation to transformation, also have several parts cars, engines, and parts laying around. Saved it from the crusher and was an auto. Then went to T9. Now has a T5 from the 88 TC I used to own and the engine from the TC that was fully rebuilt, RR cam, 3 inch DP and exhaust. After market wheels, it's not a show car but I am really happy with what it has become. Sure like everyone else here get compliments about it. "MAN I HAVEN'T SEEN ONE OF THOSE IN YEARS!" 👍

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Re: Won't idle after a short drive

Post by my8950 » Mon May 20, 2019 10:23 am

Merkurstein wrote:
Sun May 19, 2019 10:27 pm
my8950 wrote:
Sun May 19, 2019 9:16 pm
Merkurstein wrote:
Tue May 14, 2019 7:15 pm
So far I have checked the fpr it holds a solid 25psi. checked the vam and seems to be doing right, looked over the vacuum lines and can't find anything.
Not saying this is the issue, but 25psi is way too low.
Pull vacuum line off when idling, set fuel pressure to 38-42psi, put vacuum line back on.
If you can monitor fuel pressure, you should see it go down a little as vacuum increases, and go up if/when you get into boost. 1:1 ratio, 1 psi fuel pressure to 1 psi manifold pressure.
I meant the fuel pressure regulator holds 25psi on a vacuum pump. The actual fuel pressure stays around 38 to 40. The car now just has a dead miss here and there, which a lot of XRs do from what I have read.
I guess in my 20 years or so of messing with these cars/engines, I'm not familiar with this dead miss, nor have I heard or read about it.

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Merkurstein
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Re: Won't idle after a short drive

Post by Merkurstein » Mon May 20, 2019 1:14 pm

Guess I'm just speaking with my experiences mostly lol. Thought I read through out the years people having idle and missing issues. Didn't mean no disrespect or nothing, thanks to everyone for all the help.

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Re: Won't idle after a short drive

Post by my8950 » Mon May 20, 2019 3:38 pm

Merkurstein wrote:
Mon May 20, 2019 1:14 pm
Guess I'm just speaking with my experiences mostly lol. Thought I read through out the years people having idle and missing issues. Didn't mean no disrespect or nothing, thanks to everyone for all the help.
None taken, just saying, I haven't heard about issues or inherent miss-fire just because.
Usually its due to platinum plug, bad wires, or some other issue.

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Re: Won't idle after a short drive

Post by eaton53 » Mon May 20, 2019 7:09 pm

Merkurstein wrote:
Sun May 19, 2019 10:27 pm
"MAN I HAVEN'T SEEN ONE OF THOSE IN YEARS!" 👍
Or ever.
Mark Copeland - I'm 50 miles west of Kewanee, IL

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I'm just the latest caretaker and I'm keepin' it REAL shiny!! 8)

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