95 transport 3.8-egr valve???

[canaris]

I got this van for 10 years now...in the last 6 months I have changed the transmission...lower intake gasket..cause of leak...spark plugs and wires..did that one myself..my arms still hurt...ball joints tie rods..struts....andso on...

Now i have another problem..the car developed a rough idle..and when it fully warms up...and Im at the stoplight..and I am stepping on the brake and letting go..it feels like it wants to chonk out..when Iam driving it at around 2000 rpm..it feels like it wants to accelerate by itself...or if it doesn't do that it'll surge a bit...i did some research and I only come up with the EGR valve....does anybody agree with me on this one?


My question is How easy it is to remove the EGR valve to check it/replace it? Do I need anohter gasket....is there anyway for me to diagnose it without any testing equipment?..Could it be the MAF sensor?


Any answers would be greatly appreciated..



By the way the van has 156,000 Kilometers..thanks..

[LMP]

SInce this is a '95, I am not sure of you have OBD1 or OBD2....If the plug looks EXACTLY like this one
www.avigex.ca/xport/plug.jpg (with connectors in A,B and M only) it is OBD1 and you could pull the codes. With OBD2, you need a scan tool...
MAF is not a cause in what you describe. If it surges, this is most likely throttle position sensor.
EGR valve problem (like one section is left opened) will indeed provide rough idle or stall at idle, but no signifiacnt surge at highway speed.
Most likely TPS, easy to test and easy to change.
Check this out:
www.avigex.ca/xport/dtc21.jpg
www.avigex.ca/xport/dtc22.jpg

[canaris]

Thanks for the reponse LMP..This TPS....is it something I can change myself? I live in Montreal...do you have an idea how much it costs....? thanks..

[maj154]

The TPS price vary anywhere from $30 to $600, depending on the vehicule (was $600 for my RX-7). I think the one for the van are in the $50 area. Try to adjust the TPS first. You just have to turn it clockwise a few turns. If you have to replace it, it's really easy. Good luck

[LMP]

This is an easily replaceable item. $C75 at Carquest (chicoutimi).
www.avigex.ca/xport/maf.jpg
www.avigex.ca/xport/tpsloc.jpg
THis is a "pot" (potentiometer) that acts on 1/4 turn providing along that path a voltage varying from near 0.5 to near 4.5 volts. It is NOT adjustable. It is linked to the throttle valve. Be careful with little nuts and bolts in that area. As per diagram posted in previous mesage, a test can be done verifying that voltage goes progressively across the range with increasing throttle position: no steps. MOst probably, in most cases the resistance track breaks and you end up with 2 voltages: 0 or 5, and the "step" occurs at the break point, most likely around normal driving throttle position, and this continually "surges" the engine up and down for very little variations in throttle position.
Although there is a high probability that this is your problem, I suggest you make tests before . AVOID repairing by "blind" changing parts until solved, alas too often common practice. E-mail me if you need more advice on how to do tests.
I have not changed mine but once it got "dirty" - providing erratic contact - and I was able to force some WD40 inside and got back to normal. THat was like 8 years ago.

[canaris]

there is one more question I have that puzzles me...I have never seen my "check Engine" light come on ...so I disconnected my egr valve..and i still don't see a light...is this normal....or is the bulb burnt?

[LMP]

I do not know if you ran the car for a little while at highway speed for the computer to see EGR valve is not there. But I cannot rule out the CEL to be burnt....

EDIT: nicke66 remark about the linear valve adds another dimention.

Visually and electrically different from the previous 3 section model.

A faulty feedback resistor (just like the TPS) can make the egr valve wander erratically for position. Tests that are suggested in following post are to be kept for all similar cases.

[nicke66]

Originally Posted by canaris

I got this van for 10 years now...in the last 6 months I have changed the transmission...lower intake gasket..cause of leak...spark plugs and wires..did that one myself..my arms still hurt...ball joints tie rods..struts....andso on...

Now i have another problem..the car developed a rough idle..and when it fully warms up...and Im at the stoplight..and I am stepping on the brake and letting go..it feels like it wants to chonk out..when Iam driving it at around 2000 rpm..it feels like it wants to accelerate by itself...or if it doesn't do that it'll surge a bit...i did some research and I only come up with the EGR valve....does anybody agree with me on this one?


My question is How easy it is to remove the EGR valve to check it/replace it? Do I need anohter gasket....is there anyway for me to diagnose it without any testing equipment?..Could it be the MAF sensor?


Any answers would be greatly appreciated..



By the way the van has 156,000 Kilometers..thanks..

EGR valve:
94-95 3.8 has a linear EGR valve with a solenoid and a position sensor. There is a 5-pin connector. Pin 1 and 5 goes to the solenoid, and pin 2 to 4 goes to the sensor. You can check the valve with an Ohm-meter.
For the solenoid, you should read about 9 Ohm between pin 1 and 5.
For the sensor, you shoud read about 4 kOhm between pin 2 and 4. The reading between pin 3 and 2 (or 4) should vary with the position for the valve, and be between 0 and 4 kOhm. The reading between 2 and 3, plus the reading between 3 and 4 should for any position for the valve be equal to the reading between 2 and 4.

Bad connection inside the sensor is common falure, and means the sensor has to be replaced. The valve can have start going bad even if the check engine light is not on. If there is just a little bad connection inside the sensor, the CEL does not turn on.

[canaris]

Today I took it to the shop..they stuck it on the scanner....EGR vlave and TPS showed no history or trouble...I had one error code and that was the Crank sensor....75 dollars later..crank sensor is on....scanner show no trouble code....

Now here's the bummer....I took it for a test drive with the mechanic....same *&^%$ problem! surging between 1700& 2000 ..and the surging keeps getting stronger like sort of kicking on and off....back onl the scanner..back onl the road....mechanic thinks it's the lockup torgue converter..or solenoid...by the way the transmission was changed Feb/20/2005...so it's still under guaratee...except I have to lose more time with this...I am sure someone has a voodoo doll of my van....I will keep yu guys posted on the outcome of this...



thanks for the help...

[LMP]

As nicke66 pointed on, an EGR problem may avoid the CEL or a code. However, disconnecting the TCC plug on the side of the transmisison,
www.avigex.ca/xport/tccloc.jpg almost under the EGR valve, is the way several have used to confirm/deny the TCC was involved in the problem. If problem disappears with TCC disconnected, then it would be a TCC related problem (not necessarily meaning the TCC is faulty).

[nicke66]

Do the following 2 tests:

First, disconnect the EGR valve. This will make the valve to stay closed all the time. Take the van for a test ride. If the valve is causing the problem, the problem should be gone. If not, try the second test.

Second, try LMPs suggestion and disconnect the TCC plug and take the van for a second test ride.

[canaris]

I did the egr test...no change...the TCC plug ..how is that thing held on..it's kind of tricky to remove..




One more thing ..my mechanic says that the rough idle could be atributted to the torque converter....which was changed two months ago..is this possible.....I remember in the old days if you had a racing cam in an automatic equipped car and kept the stock torque converter ..it would have a hard time idiling..because the torque con. was too "tight"


But would a defective torque converter or solenoid valve in tranny affect idle????

[LMP]

Balooney. IN neutral, tight or loose torque converter just spins a free output shaft anyway. I owned a "wild cam" long time ago, and the engine would have stood alone with nothing connected and it would have sputtered and jerked from side to side anyway. In fact, those with a manual transmission just did the same eh?...
Disconnecting the EGR valve does not mean it is closed! if it is damaged, it may stick in a partly opened position......a frequent problem.
I think a visual inspection of the EGR valve is the easiest step to start with. THis option must be closed before anything else: too simple to overlook and wander all around to just find it was that from the start. it is such a frequent problem it cannot be discarded without verification. So best is to remove the valve and find a way to shut any possible exhaust recirculation. This will definitely either confirm or remove that option.

[canaris]

I did the egr test..with a ohmmeter..pin 1 and 5 have 10 ohms..but 2 and 4 have nothing no reading..and thats for the sensor is this normal?






When I umpluged the egr there was no improvment in rough idle could it be stuck in the open position?

[LMP]

OK..I guess after hte 10 ohms reading, the proper reading range was set - maual or automatic - in prevision of the 4k reading.
If you have really no contact from 2 to 4, it means the resistor track is cut. Then it means the whole section of the track hooked to the ground side is at 0 volt, and the whole part of the track linked to the supply (probably 5v) is at 5 v. This means as soon as the position of hte valve hit the 0 volt side of track, even if it was at 30% open, it interpreted that as the totally closed position and left it there. At least, this is how a feedback type control works.

A final test would be to check between 3 and 2, then between 3 and 4: you should have a contact on one side, and none on the other. If this is confirmed, you definitely need a new EGR valve. Check on e-bay.....