[WA_TRD_83]

Here's the deal:
Car starts ok, car drives nicely. However, I get the irregular 'bucking' of the car every now and again, usually more noticable after I give the car a bit of a run. The engine will sound like its running, but I'll have no response from the accelerator pedal - the tacho drops to 0rpm and the 'Check Engine' light comes on. After a couple of seconds, the car will either decide to keep going or just stall.
So far nothing has died on it, because after it stalls, a little while later I can usually start and drive off again. Therefore, i have no idea what to replace or fix, cos most of the time the car runs well.
The mechanics best guess at the moment is that there is something wrong with the computer, but before I go fork out $2000 for an aftermaket ECU - I thought i'd check and see if anyone else has had this drama and what it was.

Car details: 1983 mkII supra, 1GGEU, 5spd, old and holey 2 1/2in exhuast, stock air intake. Rest of the car is mainly stock.

Recent attempts at fixing: replaced fuel filter, replaced spark plugs, pod filter - then removed pod filter, minor service.

I just want to get it back to the reliable days! PLEASE HELP!!

Thanks
DAMO
TRD 83

 

[Square]

Could be a bad throttle position sensor.

One of the cars I "oversee" had a bucking problem, and it was caused by a dying TPS.

 

[Marblehead]

Along with Square's thought it also sounds like it could be the fuel pump going south. Does it ever buck during normal driving or ONLY after a spirited trip? Other thoughts:

Old/worn plug wires--the higher engine heat causes them to arc.
Check the timing
Blocked catalytic converter or muffler

Be one of seven lucky winners!
Scott

 

[MAD_83supra]

I would start with fuel filter, then fuel pump. It sure sounds like its starving and thats why you get the check engine light. The O2 sensor is going lean. Bad plugs and wires only goes rich and your O2 sensor wont put up a check engine light for that.

Let us know what you find.... oh, check or just put new ground wires from your engine to frame and to your negative battery post..I got caught with that problem.Alot of wierd things did happen to me similar to your problem.

 

[85TurboMKII]

my 85 was doing the exact same thing and it ended up being the TPS. real irritating.

 

[zank]

I had that same problem a while back, where my car would buck and die then start back up like nothing happened. After checking it out I found out that the Fuel Pump went bad. I replaced it and the problem was solved. Just a thought :wink:

 

[SupraFreak]

I'm having the same problem. I just replaced the fuel filter today. It didn't fix it. The fuel pump is about 6 months old. I just want it to run reliably again.

 

[WA_TRD_83]

Thanks people! All good suggestions!
I'll start with the fuel pump, because I had suspisions it could be the problem... Then I'll move on to the TPS.
Its just like ZANKONE said - starts up again and is on its merry way!!?? :?

Actually - considering that I'll hopefully be moving on to a 7M conversion shortly, is there a better fuel pump i should upgrade to for this job?

Thanks again
Damo

 

[Daves2JZGTE]

if you have a external pump witch im shore you do (their is a slite chance your pump could be inside) go with a walbro gsl 392 . thats the pump i have on my 7m if your pump is in tank get a 255hp walbro pump . now you will hear the pump its not silent so if thats a consern their are other pumps their just more expensive. Dave

 

[85TurboMKII]

yea with full interior still in the fuel pump isn't that loud. now strip the interior (like mine is) and the pump becomes very loud inside the car hehe...it's kinda cool sounding..everyone always asked me what that high pitch wining is. and from outside the car you can definatly hear it as well.

if you have a external pump witch im shore you do (their is a slite chance your pump could be inside) go with a walbro gsl 392 . thats the pump i have on my 7m if your pump is in tank get a 255hp walbro pump . now you will hear the pump its not silent so if thats a consern their are other pumps their just more expensive. Dave

 

[Daves2JZGTE]

i was pm ed about the pump hp limits and cost so i thought id share with every one. thats a tricky question as far as hp gose. so can the pump flow enuf gass at x power or presher. it works like this your car has to run x amount of presher in the fuel rail to feed the injectors. a stock 7mgte runs about 28psi in the rail at idel or vacume. at 0 psi it will jump up about 10 psi so now your at 38psi(if your set at 26 it still gose up about 10psi to 36). so now you add boost your rising rate fuel presher regulater should be a 1 to 1 with a 7mgte ( 1 pound of air 1 pound of gas). if you run 8 psi of boost you just add 8 to 38 to = 46 psi. and so on like 15 psi boost = 53 psi fuel rail preasher. ok now can your pump keep up with the demand if you look at the chart http://www.autoperformanceengineering.com/pics/gsl392.jpg
you will see that at 60 psi the pump will flow about 52 gph (gallens per hour)
http://www.jblmk3.com/id82.htm
if you look hear you can see a stock mk3 pump is down to 8 gph at 60 psi
now you would have to do some math to see how much hp you can get you take injector size and pump that will give you a # thats a ruff # but this pump will be the last pump you will ever need for a 7m of any modding
as far as price gose i got mine for cost but you can get one of the net for about $125 to $160 i hope that helps you out.
Dave

 

[WA_TRD_83]

Progress Report
Ok Guys - here's what I know so far...
The Supra has been at my uncles (who is a mechanic) for 3 days now! I told him of the suspicious fuel pump. He tested it and it appears to be functioning and flowing perfectly. :?
Next we tested his suspicion, the ECU. Sent the ECU off to be checked out. It was pulled apart, tested, and sent back. Everything tested out ok. :? Another day down the drain.
Today he started checking out the rest of the electrical system. He noticed whenever he tapped the coil - the engine would stall. Source of the problem?? Hopefully this time! He has sent the coil off to a specialist to test and repair if necessary.
So with fingers crossed I should have my reliable Supra back tomorrow - If this is the source of the problem...

Anyways - hope this can shed some light for those having the same / similar problem.

I'll let you all know if it is definately the case when its been fixed and what was actually wrong, I know I'm a little sketchy with the details at the moment.

Cheers
Damo
TRD 83

 

[Glaucus]

Hmmm... wierd... in that case you should have stalled every time you went over train tracks or hit a bump. Did you notice any corollation between bumpy rides and stalling?

- Mike

 

[shiva]

if your tach is dropping to zero when this happens but the engine still seems like it's running, and the ecu is ok, your igniter is probably on the fritz. the igniter has a tach signal output.

i'd test your igniter. if you can't swap in a known to be working one, the haynes manual has a good way of doing this, just be careful not to keep the battery hooked up for anything longer than a split second.

shiva

 

[Dave A.]

Hmmm...I didn't know that any MKII's came with the 1GGEU. Was this a swap? I would look real close at the igniter as being the culprit. Tapping on the coil really shouldn't make the coil act up since it's basically a solid mass. The igniter OTOH could possibly act up if it's jarred hard enough.

 

[Black Dawg]

definitely sounds like something in the ignition system..... coil or ignition module.

 

[WA_TRD_83]

And we have a winner...
BLACK DAWG was right in this case. Twas something to do with the ignition system, and more specifically it was the ignition module playing up all this time!
So i got my Supra back from the workshop on Friday last week after 5 days of trial and error. Finally the module was replaced and problems ceased. The vehicle was placed back in my capable hands for a weekend of driving to see if the problem would re-occur, and to this day it hasn't cut out on me once!! :shock:
I'm sooo enjoying a trouble free Mk2 again! Now I just got to replace the stereo that some punk ripped off while it was out of action and I'll be back to cruising the coast in no time!!

by the way DAVE A. - this was not an engine swap. The 1GGEU came standard in my car. i don't think there was too many of them, but it matches the manufacturers plate on the car ...

Thanks for all the help fella's - hope my findings helps out a few others!!

DAMO
TRD 83

 

[SupraFreak]

Did your car start smoking when it started dying? I'm still having problems after changing the TPS and AFM. Still need to fix it. Any help would be great.

 

[WA_TRD_83]

hey SupraFreak
I'll assume you were talkin to me.. and no it didn't start smoking..
whats smoking on your car? and what colour smoke?
sounds like a fuel situation? maybe check your fuel pump or replace your fuel filter??
Any other symptoms?

DAMO
TRD 83

 

[MK2SupraP83]

i'm haveing the same problem! mine is good for about a 10 minute run then it happens around 3500 rpm. and it gets worse the further i drive it untill it woln't go anywhere. but it never acually stails out. then if i shut it off for a bit its ok again, for abotu 5 mins. i replaced the fuel filter, got new plugs. the fuel pump should still be good it was replaced last year and hasn't been run much since. so i thought it might've been the distributor. i replaced the cap and roter but it didn't help. i have afm on the way. dunno if it will help. but i guess i'll try the igniter too. Were is it at and how much would one cost? btw whats TPS mean?