Help... Please... Motor woesssssss

[RWKHausSupply]

Ok well I have done the following.

Bought a 90, 4.0, AW4, motor had a rod bearing missing and bad off.

• Replaced long block with reman. with a build sheet and run spec of all the vitals.
• Replaced injectors with reman ones that had a spec sheet, all look great
• replaced TPS set to .335 at idle and 4.2 at full throttle
• replaced MAP
• replaced Ign Coil
• replaced fuel pres. reg.
• replaced O2 sensor
• replaced cap rotor and wires and pluds
• replaced intank air temp sensor
• replaced ECU (same results from both)
• replaced the idle air control valve
• I have removed the TB and removed all sensors and throughly cleaned it.

OK issue...

After motor replacment it runs great cold and then after it warms up, about 90% of the time when stopped and tring to take off at a med pedel it will back fire very lightly and not want to go. Once moving it feels as strong as a 90 should I would think.

I have tested EGR and even discon. it and same issue.
I have removed all non-essintial vac lines and plugged ports, same issue.
I have spreyed down the entire upper area of the int man with break and parts cleaner looking for a vac leak, no changes in idle.
I have tried Everything I can think off really.


NOW..

Anyone in so cali that can find the issue I will pay a fair fee to, if they can find the issue. I checked the distrib and the shaft has no play. The only thing I can think off is the manual air adjustment idle screw. It was all the way in when I got it and it would not idle right after the new motor, so I opened it up some and it idled fine. But now with the ALL the new parts I think that was something else and now that that screw may be causing a rich or lean off idle issue??

Please anyone help.. I am in to this way to deep with new parts and $$

Oh ANYONE that has a renix 4.0 that can count the number of turns that it takes to close (clockwise) the manual screw on Throttle body on the drivers side I WILL be in debt to ya... It wouldnt cause any issiue for ya if you just counted the turns in then just returned to that many out. Please.....

OR anyone have a TB from a renix that has not been tampered with? I will buy it from ya. Let me know..

HELP! I need to move on to the rear end adn gears and cage but not till this is resolved.

 

[MJR]

The EGR can still open with exhaust backpressure if the spring is weak. Usually when setting the TPS (you didn't say it was replaced) it's done on the trans side (two sided) vs the engine side. I'd make sure on the 3 wire connector you don't have a dead spot as the throttle is opened. The screw you are reffering to is a factory minimum air flow for the throttle body and as I am sure you know it shouldn't have been messed with (I know it wasn't you). The best I could do there is measure from the TB to the throttle link and tell you what it is (Sun maybe unless someone else can sooner). Crappy plugs/wires can cause problems or incorrectly gapped plugs. The CPS might cause a problem when warm if the voltage isn't as high as it should be (disconnected and cranking motor the voltage from the sensor should be between .5 and .8V AC). I'm in Costa Mesa if you ever want to have it looked at (I have a factory scan tool also).


Mike R

 

[RWKHausSupply]

MJR, yeah I replaced the TPS (4th item up there I think) and set it to the.335mV at idle. The EGR when running and not moving and inspecting the valve I cant get the spring to open with applting throttle, do you think it would be any different while driving or under loads?

 

[AJPulley]

My EGR is also unplugged do to the close signal not reaching the EGR solenoid, so the vacuum line is plugged. I still have no issues with idle or emissions. But, even when I hook up the hose (constant vacuum with no signal from ECU) the engine still runs well enough to drive all day long, with the old and new EGR valve. I don't know if that helps you at all.

Check for a crack in the MAP harness. I had used a tiny vacuum hose when mine cracked, and had all sorts of problems- I think due to the fact that hose isn't rigid enough from even the slightest amount of colapsure. But a small brake line worked perfectly until I finally replaced the line with the new engine.

On my throttle body, I reset base idle and adjusted the throttle plate. So, I had my stop screw backed out until the throttle plate made contact with the bore of the body, then screwed it in about a half turn, maybe a little less if I remember. But, I have a manual tranny, so an automatic may need a little more air at idle, I don't know. My ECM controlled idle when warm is about 500 RPM. If you really need to know about the number of turns, I have a spare in the shed that came out of an auto and can go count, but it's cold out there.

Did you check the remaining sensors, including the temp sensor values at a known temperature? What about fuel pressure when warm while hooking up an external high vacuum source?

It sort of sounds like a rich fuel mixture when warm and it's in open-loop mode.

Do you have a Renix manual?

 

[MJR]

My EGR is also unplugged do to the close signal not reaching the EGR solenoid, so the vacuum line is plugged. I still have no issues with idle or emissions. But, even when I hook up the hose (constant vacuum with no signal from ECU) the engine still runs well enough to drive all day long, with the old and new EGR valve. I don't know if that helps you at all?

A properly working EGR should choke and stall the motor while idling when a vacuum pump is used to put vacuum directly at the EGR valve.

Check for a crack in the MAP harness. I had used a tiny vacuum hose when mine cracked, and had all sorts of problems- I think due to the fact that hose isn't rigid enough from even the slightest amount of colapsure. But a small brake line worked perfectly until I finally replaced the line with the new engine.

The factory vacuum line should be rigid plastic with rubber ends where it connects. If it's not it certainly could get softer when warm and cause problems.


Mike R

 

[RWKHausSupply]

well dont know what exactly fixxed it but I think it might have been something Very odd to factor in. The tailpipe hanger at the TC skid was not there I found a few weeks ago and bought a new plate with it on there for the tailpipe. Well without it there the pipe would hit the skid at idle, randomly and when first taking off it would hit. Well I have to think that its poss that it was causing the knock sensor to poss get a false knock and that was f'in with the timing and causing the issue. I used a hose to isolate the knock and it was very strong all the up to the block but was found to be that skid to tail pipe are that was causing it.

It is poss though that that was not it cause I also removed the TB and replaced the gasket, then fabed a hard brake line from the TB to the MAP, and screwed in that idle bypass screw all the way and turned it out about 1/2 turn. After all that it no longer has any issues.

One good outcome of all this, I have a complete new engine pretty much now. I mean I replaced everything except the temp sensor and the distribitor. So thats a perk I supose....

 

[MJR]

well dont know what exactly fixxed it but I think it might have been something Very odd to factor in. The tailpipe hanger at the TC skid was not there I found a few weeks ago and bought a new plate with it on there for the tailpipe. Well without it there the pipe would hit the skid at idle, randomly and when first taking off it would hit. Well I have to think that its poss that it was causing the knock sensor to poss get a false knock and that was f'in with the timing and causing the issue. I used a hose to isolate the knock and it was very strong all the up to the block but was found to be that skid to tail pipe are that was causing it.

It is poss though that that was not it cause I also removed the TB and replaced the gasket, then fabed a hard brake line from the TB to the MAP, and screwed in that idle bypass screw all the way and turned it out about 1/2 turn. After all that it no longer has any issues.

One good outcome of all this, I have a complete new engine pretty much now. I mean I replaced everything except the temp sensor and the distribitor. So thats a perk I supose....

Hope it works good from now on. If you are worried about smog pay for a pre test, it's worth it. When I have to go to a test only place I always pre test it. One year it needed a cat/decarb and 2 later an O2 sensor, always passed at the test only place. I need to do a pre test again and maybe a decarb, hopefully thats all it needs this year.


Mike R

 

[RWKHausSupply]

well I just bought it and they didnt require a smog only station so I am going to perfect auto with my 19$ coupon from a competitor and having it done for the 19 + certif. it should pass I think. I mean its basically all new except the cat adn thats only like 2yrs (10K miles) old from the reciepts I got.

Now I can finially move on to the 8.8 rear and all its needing with the install and extra's..