Hey guys fixed all the problems I had before when I posted with the HO motor and truck intake and electronics.My problem now is the truck surges up and down at idle.I have checked and checked thinking it was a vacuum leak but I can not find anything.Any other ideas.I pulled codes doing the koer test and found these codes,12,42,77 and 52. Does this help at all.Thanks

 

Did you try to clean your IAC out? Thats the most common for idle surging.

 

Yes I cleaned the IAC and the intake as well as the EGR.It seems to be worse when the engine warms up.I set my base timing at 12 degrees and as well I unhooked the ignition module and still made no difference.I took brake cleaner and sprayed the whole engine in look for vacuum leaks and the rpm did not change.

 

Did you ck your tps voltage? It should be like .9-1v at ldle and 5v or close to it at wot. might be getting some play in it. Have you tried spraying intake cleaner into the TB? sometimes gunk can make it idle wierd.

 

no I have not checked my TPS voltage. Will that cause it to surge if it is out of range at idle? Will check!!!Any other thoughts

 

Straight from www.fordfuelinjection.com:

<TABLE style="FONT-SIZE: 100%" cellSpacing=0 cellPadding=2 border=1 table><TBODY><TR><TD>#</TD><TD>KOEO</TD><TD>CM</TD><TD>KOER</TD><TD>Code Definition</TD></TR></TBODY></TABLE><TABLE style="FONT-SIZE: 100%" cellSpacing=0 cellPadding=2 border=1 table><TBODY><TR><TD>12</TD><TD></TD><TD></TD><TD><CENTER>X</CENTER></TD><TD>Cannot control RPM during ER Self-Test high RPM check.</TD></TR></TBODY></TABLE>
<TABLE style="FONT-SIZE: 100%" cellSpacing=0 cellPadding=2 border=1 table><TBODY><TR><TD rowSpan=2>42</TD><TD></TD><TD><CENTER>X</CENTER></TD><TD></TD><TD>HEGO sensor circuit indicates system rich (right side).</TD></TR><TR><TD></TD><TD></TD><TD><CENTER>X</CENTER></TD><TD>No HEGO switching detected always rich (right side).</TD></TR></TBODY></TABLE><TABLE style="FONT-SIZE: 100%" cellSpacing=0 cellPadding=2 border=1 table><TBODY><TR><TD>77</TD><TD></TD><TD></TD><TD><CENTER>X</CENTER></TD><TD>System failed to recognize brief WOT during Dynamic Response Test (user error).</TD></TR></TBODY></TABLE><TABLE style="FONT-SIZE: 100%" cellSpacing=0 cellPadding=2 border=1 table><TBODY><TR><TD>52</TD><TD><CENTER>X</CENTER></TD><TD><CENTER>X</CENTER></TD><TD><CENTER>X</CENTER></TD><TD>Power steering pressure switch always open or closed.</TD></TR></TBODY></TABLE>Code 12, yup, that's what it's doing. No surprises there.

Code 42, KOER, possibly dead O2, bad/dead heater circuit to O2, broken wire or bad connection to O2.

Code 77, umm, gotta punch it when the ECM tells ya to. And I mean punch it too. About 1/2 second, minimum. You'll probably pinch a hole in the seat when you do.

Code 52. This sort of indicates an ECM for a manual tranny. Trucks equipped with M5's use a power steering switch, but not the ones with auto tranny's. Otherwise, that code would be neutral safety or MPLS (Manual Position Lever Switch). 52 is a dual function code depending on the application. If you have an ECM for a manual in a truck with an E4OD, though, that probably ain't gonna work. Didn't see that info in this post.

Otherwise, the hunting idle is suggesting a vacuum leak, or if you've done any intake mods or exhaust mods which are causing pulses in the vacuum signal to the MAP, the ECM will go bonkers trying to control idle. If you have an SO ECM on an HO engine, that's another possibility. The HO has a much different intake profile and moves a lot more air.

The good news is, the ECM thinks everything's OK, and seems to be working well. The bad news, everything's NOT OK, obviously. I found my ECM WILL NOT help with vacuum leaks unless it's bad enough to indicate a lean condition with the O2 (42) or hose up the signal from the MAP. Umm, you got a 42, classic symptoms of vacuum leak, and possibly didn't get all the codes because of the user error (77). Gotta make the test complete. If you don't stomp the crap out of it during the test, and don't rotate the wheel when it's time, you won't get all the codes. The test aborts on the 77.

Oh yeah, if you DO have a manual tranny, fix the PS pump switch. Can't remember if it's closed and opens when pressure goes up, or open and then closes, but if it ain't in the right state, it's probably trying to compensate thinking there's a load on the PS pump. That may cause some surging too.

 

I keep coming back to a vacuum leak too.These trucks always surge with a vacuum leak.I will get a vacuum gauge and go from there.As far as the controller and engine,I only used the long block of the stang,I even used the E7 heads of the truck.I also noticed that the truck has a pressure sensor down by the power steering so I was figure there was something wrong in that circuit.I have not done any mods at all to anything YET!!!!! Thank you will post back!!!

 

Ok guys.Just checked the tps and voltage is .88v at idle and 4.6v at wide open.I sprayed every vacuum line in the book and it had no effect on the idle.What else is kind weird is that when I started the truck stone cold it ran for 10-15 mins perfect,idle perfect and did not surge.It was all of a sudden after 10-15 mins it begin to surge.Its almost like something is coming on or something after that time.As well if once it begins to surge I rev it up and "clear it up" it idles perfect for 30 secs and then surges.Whats going on!!!

 

Id start to unplug vac lines and then plug them off on you truck and see if that makes the surging stop.

 

Old_Paint's Vacuum Leak Detection Procedure.

1. Disconnect EVERYTHING except the MAP sensor and fuel pressure regulator from the plenum vacuum tree. This includes the brake booster as well.

2. Seal off all nipples there.

3. Loosen EGR valve at plenum. Use gaske for a template to cut a steel block-off for the EGR. Re-install EGR with block-off.

4. Disconnect EVAP cannister connection at throttle body.

5. Connect vacuum gauge at nipple for EVAP cannister purge line.

6. Crank truck and let warm.

7. Check vacuum at warm idle. Should be close to 20 in. Hg with PCV still connected. Anything less than 18, you have a leak, and it AIN'T a hose unless it's the MAP sensor tube.

8. If step 7 indicates a leak, use an unlit propane torch to aim propane at all sealing surfaces. Check around the tree, the upper/lower intake joint. around the fuel injectors, and where the lower intake meets the heads.

9. If no leak is indicated by step 8, disconnect PCV valve and seal inlet to plenum, and re-check.

10. If vacuum is good in step 7, reconnect vacuum hose to brake booster. Recheck. If vacuum deteriorates, but no leak is detected with the propane on the hose or around the fitting on the booster, chances are, the diaphragm in the booster is leaking. (Having hard pedal issues with brakes too?)

11. Reconnect red vac line to Vac reservoir on fender well. Recheck the following items: Red tube to vac res, black tube from vac res to EGR/TAB/TAD manifold. EGR should be closed, but check the green tube anyway. Also verify EGR is closed. Check TAB/TAD lines (yellow and pink).

12. Reconnect vacuum line to cruise control vac res. This is teed into the brake booster hose on mine. I think there may be a few variations on this design. Check the line to the reservoir, and from the reservoir to the servo for the cruise control.

13. If you have a C6 tranny, there will be a line that goes from the intake to a modulator valve on the rear of the tranny. Reconnect this, and re-check vacuum. Normally, the type of leak failure on this line is a failed diaphragm in the modulator valve. This is normally accompanied by disappearing tranny fluid. Sometimes there is a vacuum manifold mounted on the firewall. Vacuum circuits in theory may be identical between model years, but exactly how they were implemented or routed may vary widely.

14. Loosen the EGR and remove the steel blocking plate installed in step 13. Retest intake vacuum.

15. At this point, you should have tested everything except the EVAP cannister connection. Disconnect the vacuum gauge, and the red line to the vac reservoir. Connect the vacuum gauge to the evap reservoir connection nipple, and reconnect the evap cannister connection. Retest vacuum.

Somewhere along the testing, you should see a very significant change in vacuum. Even a small change, if you're hanging on the edge of the tuning/learning of the EEC, may affect driveability and cause the hunting idle. In this case, it may be necessary to reset the EEC's fuel tables. This is done by disconnecting the battery for at least 15 minutes. There will be some poor mileage while the EEC re-learns the fuel tables. Normally, about 100 miles of normal driving will handle the learning period.

 

Wow old paint that was a great post.I will get a vacuum gauge and check on Monday thanks! Will post back!!!

 

ok guys this is what I found.I started the truck with everything unhooked except the fpr and the map sensor.My vacuum was 18. As soon as the idle started to come down the vacuum would start to fluxuate from 18-16 and then 15 when the surging got really bad. I changed every sensor with a know working truck and no difference. I took the upper intake off and the gasket looked ok.I have sprayed and sprayed either around it and nothing.SO now where,Is it possiable that the lower is leaking or what else worried me is that the upper and lower might have been cleaned with a dye grinder and now the surfaces are not true any more.Point me in the next direction.The other things that I am wondering is the lower might not be true as well.I just put all new gaskets in this engine.The lower did have pitting.Help me in the next step.....Happy New Years!!

 

My 88 351W starts surging after the truck is warmed up.
What engine do you have ??

 

Old hog hauler
After you have done everything you can, but before you get cranky, try this. Worked for me.
Good Luck Frank

http://mustang.c-f-m.com/index.asp?P...ROD&ProdID=649

Ford Idle Air Adjuster Kit for '86-93 hide F2PZ9F939A
List Price Qty
$47.86 $40.95

 

The engine is a 302.Anyone have any ideas