VN Commodore running rough help

[Cheap6]

hey everyone this is my first post on this site..
having problems with my 1989 VN Commodore it starts but idles bad, its running on all 6 and when i put it in another gear like drive or reverse it almost stalls and sounds like its thirsty for petrol this only happened after i tried cranking the engine over without much fuel in it, i understand the fuel pump can stuff up doing that, but after putting petrol in it it still starts fine ? just runs really bad, and smells like petrol also black liquid most likely condensation mixing with exhaust fumes is coming out the exhaust PLEASE HELP cheers also blows out a decent amount of black smoke.

Anything that causes a misfire can cause the engine to run rich because the O2 sensor only looks for O2 in the exhaust not how it got there. If the fire isn't happening there will be unburnt O2 in the exhaust and the ECM will try to correct that by adding extra fuel.

Try some basic things like spark plugs and leads (inspect first before you spend money). It's possible that the engine has a mechanical fault, like a manifold vacuum leak - gaskets or injector 'O' rings are two possibilities - or a burnt (leaking) exhaust valve. All the injectors normally flow the same amount of fuel so if you have one cylinder getting more air than another they will run strangely as it runs lean and the others run richer. Vacuum leaks will be most apparent at idle so if the engine runs more smoothly under load that may be an indication that is where the problem lies.

If it is actually running rich and there's nothing else wrong with the engine, the ECM's have been known to fail such that they read the engine coolant temp. sensor low.

hmm, it's weird though because when i removed the hose i squeezed the top hose and i felt with my finger the thermostat moving up from the pressure this happens with the thermostat housing on as well big problem or ?

No, it shouldn't be doing that. If the thermostat isn't working properly the engine temperature will be varying more than it should. The coolant temp. sensor for the ECM is close enough to the thermostat that it might be affected by that also and not reading the true engine temp.. As it's a fault and not expensive to replace, definitely fix it.

Hi I am new to this site, if the following post is in the wrong place please direct me thanks.

It probably would have been better to start a new thread but we can deal with it. Next time hey.

I have recently installed a complete motor and auto transmission in to a VP that was 5 speed manual. At start up the engine runs rough for about 15 seconds then revs up (2k) then drops down to 1k and runs smooth. Took the car out today for its first run and found that the trans won't change gear, if I put it into extra low gear then shift to second there is also no gear change. I have the original ECU in the car and the engine light is on, could it not be changing because the system is in 'limp' mode? I am going out now to try the reset options I found in this site. Any comments would be much appreciated. Thanks

You should swap the original 5 speed MemCal (swapping the whole ECM works too but isn't necessary) with one for an automatic transmission. The MemCal is the blue plastic bit inside the ECM. Try to match the MemCal to the engine/trans./car build date as there were (are) running changes made within ostensibly the same model. The build date of the donor is OK unless it's close to the cut off date for the changes. The gold standard is to use the VIN. Newer is not always better (it is sometimes). There are a few lists of the MemCal ID's around. The Id is in the letter combination on the sticker on top of the MemCal.

Hi VNCommodoreBraah, did an engine light test and came up with code 33 MAP sensor, found that it was not plugged into the throttle body. Plugged it in and started engine, it ran smoothly first go, then checked engine light again and came up with code 33, have taken out engine fuse at the moment while I get a cuppa and write this. Prior to engine change I never had any error codes come up, so do MAP sensors just die?? Thanks in advance.

Seldom and then usually because they've been subject to a backfire and pressure spike.

OK, took the car for a run, purrs like a lion (extractors and 2/34" exhaust system) anyhow, it would change into second at about 40km/h revving at 4K. My son has a stallie in his VY and the VP appears to react the same way. He said it is as if the VP has the power switch is on (it doesn't have one) When the VP was a manual we never had to drive it this hard for gear changes (never did) Also the kick down did not work, should there be a little tension on the cable at the throttle or should it be loose. Another also I haven't been able to find out anything about a plug just forward of the speed sender on the gearbox, I have also adjusted the shift linkage to gearbox so that there is no play( should there be some play?) And it does not run sluggish.

The Throttle Valve (TV) cable for the trans needs to be adjusted. On the throttle end is a metal button. Push that in and the TV cable tension will be released. Then open the throttle until it hits the stop, dragging the TV cable through against the ratchet. That should be it. If the cable doesn't hold the adjustment then it's time for a new one.

The plug sounds like the one for the Torque Convertor Clutch (TCC). To ID it, it has spaces for 4 pins but only 3 wire terminals. Off the top of my head I don't know which wire does what but one of them at least is earthed by the ECM to apply the TCC. Without it connected you won't have the TCC lock up. It might be tempting to just leave it but not having it will cost in fuel and the trans. will run hotter because it's slipping more. If you can't find a wiring diagram I can post up what goes where if you want.

 

[TONY4]

Hi cheap6, thanks for your comments and duly noted, with regards your second paragraph when I was still running the 5speed I cut the baffle off that goes into the inlet manifold and found that I was using less fuel and the engine was sounding a lot quieter(exhaust end). With regards the TCC plug I did keep the wiring that it was connected to and yes a wiring diagram would be much appreciated, thankyou.

 

[Cheap6]

For the TCC connector, the grey, red trace wire goes to pin A7 at the ECM (and a splice to the ALDL connector, top row, 3rd pin, next to the brown with white trace CEL earth wire). That one's the earth for the TCC lock up. The power for the TCC is on the pink, blue trace wire, connected to the fuse in the fuse box under the steering column. The 3rd wire, light blue, is earthed through the trans. oil temp. and 4th gear switches inside the trans.. That's connected to C7 at the ECM.

There is also a Park/Neutral switch that earths ECM pin B10 when, oddly enough, the trans. selector is in P or N. That switch and the auto. MemCal are for idle speed control and to enable the TCC lock up.

Dr Bob on here has a business remapping MemCals and has a supporting site with some wiring diagrams and a list of the MemCal applications. That's called Creative Calibrations. You can search for that as easily as I can so I'll leave it for you to find.

 

[TONY4]

Cheap6 thanks for that I'll look him up. Took the car for a run today (at my sons insistence) when we started off the trans changed to second at about 50klm and third about 60/65. A bit further on down the road after we pulled up to check for any leaks and took off again the trans changed about 35/40klm and then next gear at 55/60klm. Got the TV cable adjusted just right and everything is just sweet.,
A BIG THANKYOU to all you guys for your help and advice!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Please direct me for this question, as the ignition barrel is shot in the car I want to put a push button start(with accessory switch) in. Is there a thread dealing with this? I can't seem to find anything.
Thanks once again.

 

[Circlotron]

i replaced the thermostat and thermostat housing and when i squeeze any of the hoses, i can here the thermostat moving around ?

Many cars I have had do this. Some thermostats have a small bypass valve to let air get past when you are filling it up. When the water tries to flow though it it moves upward and blocks the hole. The sound you can hear is probably the valve jiggling up and down. Here is a pic of one where you can see this valve near the edge of the 'stat.

 

[VNCommodoreBraah]

yeah cheers for all the info and reply guys, i just picked up a nice clean vp commodore for $700 runs good, so im thinking to get rid of the vn or scrap it not to sure.

 

[hi_ryder]

yeah cheers for all the info and reply guys, i just picked up a nice clean vp commodore for $700 runs good, so im thinking to get rid of the vn or scrap it not to sure.

take as much spares as you can for the vp, you never know what will die and when. can tell you how many times the parts car has saved my daily driver from being off the road...

 

[VNCommodoreBraah]

take as much spares as you can for the vp, you never know what will die and when. can tell you how many times the parts car has saved my daily driver from being off the road...

yeah mate i have stripped most of the useful parts off and sell the rest to the wreckers