Where's the EGR??
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Where's the EGR??
I think I need to replace my EGR valve and can't seem to find it. Also, if anyone has ever had probs with their EGR valve going out, I'd like to know the symptoms to look for.......... thanks and Happy Holidays
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From: UT
'86 and '87 2.9's had an EGR sytem. '88-'90 2.9's didn't have an EGR system. You didn't say what year, so I just wanted you to know that it's possible you don't have an EGR system to find.
When present, the EGR valve bolts to the underside of the throttle body. EGR pressure sensor is bolted to the throttle body and connects to the EGR valve by a vacuum line. EVR solenoid, on mine anyway, is attached to the fender behind the air filter housing.
EGR faults will cause various driveability and idle problems. 1st thing I'd do if I suspected an EGR problem is pull the codes and see if the fault is one the computer can see. The computer can see many EGR problems. Codes can be pulled using a paper clip and a voltmeter. Instructions can be found in Ken00's tech info post, pulling EEC-IV codes (or something to that effect).
When present, the EGR valve bolts to the underside of the throttle body. EGR pressure sensor is bolted to the throttle body and connects to the EGR valve by a vacuum line. EVR solenoid, on mine anyway, is attached to the fender behind the air filter housing.
EGR faults will cause various driveability and idle problems. 1st thing I'd do if I suspected an EGR problem is pull the codes and see if the fault is one the computer can see. The computer can see many EGR problems. Codes can be pulled using a paper clip and a voltmeter. Instructions can be found in Ken00's tech info post, pulling EEC-IV codes (or something to that effect).
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From: UT
Pulling codes is an important diagnostic tool. I'd start by figuring out why you can't get the codes pulled. Make sure you're following a good set of instructions and following them correctly. It's possible that there's a bad connection between the self-test connector and the computer.
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From: UT
It's operated solely by vacuum. Vacuum supply to the EGR valve is regulated by the EVR solenoid. You can test the EGR valve itself using a vacuum pump. The vehicle repair guides at www.autozone.com have a procedure for testing the EGR valve. The reason I want you to figure out the EEC side of the EGR system, though, is that the EGR valve itself isn't usually the problem. EGR problems are usually the EGR pressure sensor or the wiring to the computer.
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aha! well, in that case, I need to figure out why I can't pull a code. I replaced the EGR valve to no avail. I actually sheared one of the retaining bolts off the valve and had to tap it out.
My prob is this: '87 B II running way rich and feeling like it's running on only 4 Cyls. Backfires, way slow aceleration, a little smokey, replaced EGR/ no-go.
Any hunches Mr Shorty??????
My prob is this: '87 B II running way rich and feeling like it's running on only 4 Cyls. Backfires, way slow aceleration, a little smokey, replaced EGR/ no-go.
Any hunches Mr Shorty??????
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Postmaster
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From: UT
There are many parts of the EEC-IV system that can cause this, which are difficult to diagnose until you get the codes pulled. Places like Autozone can often pull codes for you, but they don't always know how to handle the EEC-IV system, either.
One common non-EEC-IV culprit for the symptoms you describe is the fuel pressure regulator (FPR). It's diaphragm ruptures, which allows excess unmetered fuel into the intake which causes the engine to run really rich. Run the engine for a bit, then pull the vacuum line off of the FPR and see if there's gas in this vacuum line. If yes, then the FPR needs to be replaced.
One common non-EEC-IV culprit for the symptoms you describe is the fuel pressure regulator (FPR). It's diaphragm ruptures, which allows excess unmetered fuel into the intake which causes the engine to run really rich. Run the engine for a bit, then pull the vacuum line off of the FPR and see if there's gas in this vacuum line. If yes, then the FPR needs to be replaced.
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Updated progress (or lack thereof)
Saturday noon.....attempted to pull codes once again, this time using 12 volt test light. I hear a clicking coming from the area I would assume the PCM is located (Pass. side firewall, engine side) No pulsing light. Going to purchase analog multimeter, I need one anyway. Manual says jumper wire from S-T input (single) to terminal 2 which is to the right of the top two. Positive on battery and ground on terminal 4 which is second from right on bottom 4 terminals. Is this accurate in your experience?????Thanks again for all the help man...
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From: UT
It's hard to tell from a verbal description, but it sounds approximately right. Try looking under tests at www.dalidesign.com/hbook/eectest.html Also be sure to follow the test procedure correctly. I've seen some people who turn the key on before jumpering STI to SIG RTN, which results in no codes being output.
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I had same problem that you have my bronco is an 86 with egr. scaned for codes and got 31 probably an electrial problem bad sensor ,soleniod,or wire that controls egr system. I checked everything in that system and could not find problem somewhere I am missing something??? What I am doing now so I can run truck is I removed 86 ECM and installed one from an 89 bronco this new ECM does not need input from egr system and engine seems to run fine. If you find problem with your truck please post it I will try same repair on mine Any one else have any ideas????????
