Fuel issue? Timing issue?

[blue7mgte]

Hola supramanics! So I have issue, when the motor is in park and I rev my motor is fine, but when I put a load on it and push past 2500ish I get what seems to be a misfire/putting feeling. It still pushes passed the rpms but just not a lot of power. I've checked my innercooler hoses and everything is fine, it has new spark plus and ngk wires, I've also messed with the timing and have it facing all the way to the left but still does it...I'm stumped :aigo:

 

[hvyman]

Did you set the ignition timing with a timing light? If not you need to.

 

[blue7mgte]

Not yet, I need to rent one from the autozone, I tought I could just do it by trail and error but I'll be sure to get that light and do it that way tomorrow. I'll update the post after I've tried the timing light. Thanks.

 

[ClutchRR]

no engine codes?

 

[blue7mgte]

Just timed it and same issue, no engine codes( the light works so it should show a Check engine light for codes, right?) I notice that if i hold the gas Pedel at a certain angle while I drive it( which is between no gas and badly anything) it drives Alittle better but still has a slight mis but anything more and it goes nuts, still climbs the Rpms but with a miss

 

[radiod]

Check and see if you're getting a good connection in to the coil packs on the wires. Sometimes they don't sit nicely in the socket and get a crappy connection. Also did you do the timing with the jumper in place as per the TSRM? What was the condition of the spark plugs that came out? If they were running lean enough to cause this bad a miss you would likely see it on the plugs.

 

[ifyouaint1sturlast]

My first impression is that if it revs fine with no load, but then breaks up with load.. it would mean that you have a weak link somewhere. Again, I would think it's a weak link, and not an actual "something is bad" problem - if that makes sense.

When did this start happening with your car? What did you change right before it happened? I would bet my money it has something to do with the fact you messed with the timing. It needs to be on the correct tooth at the correct degree.

I know some people have recommended things, here's a list (in order) of things I'd try if this were me:

1) Check your codes. This should ALWAYS be first when diagnosing any problems with your car. (click here)
2) Check/verify your timing to be 10 deg BTDC, with T1 and E1 jumpered in your diagnostic box, with the engine warmed up (click here)
3) Check your grounds on your coil packs, there should be a ground going to the head. Maybe try the "igniter ground mod". (search for it)
4) Replace your spark plugs. It's cheap enough, can't hurt, and may fix your issue. Your old ones may not be gapped correctly. Make sure they are gapped correctly, check the TSRM for gap information.

Bookmark this link:
http://www.cygnusx1.net/Supra/

It's got links to the TSRM (repair manual), TEWD (electrical diagrams), EPC (part catalog), and how-to guides by the owner.

 

[blue7mgte]

hmmm, so during timing it is critical to have the jumper in place? if so then that maybe my problem.. but i will also check everything else, the spark plugs are brand new as i recently did my head gasket. im not getting codes as my check engine light is not on as i drive but it would not hurt for me to check thanks for the help, ill be sure to update soon as i follow through with the given advice.

 

[hvyman]

most codes get stored. light may flash or may not. But just going by whether the light is on or not doesnt do any help.

 

[ifyouaint1sturlast]

hmmm, so during timing it is critical to have the jumper in place? if so then that maybe my problem.. but i will also check everything else, the spark plugs are brand new as i recently did my head gasket. im not getting codes as my check engine light is not on as i drive but it would not hurt for me to check thanks for the help, ill be sure to update soon as i follow through with the given advice.

Nice to see someone actually take advice

Yes it is required to have the jumper while doing timing. I can't remember a time where I had a code stored that the light actually came on - most codes don't cause the indicator to light up.

Let us know how it goes!

 

[AJ'S 88NA]

Have you done this http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=101 ?

 

[90mkiiisupra400hp]

If your your timing is good with the jumper wire in, you have no stored codes, grounds are good, and you check/change your plugs, the next thing I would do is adjust the TPS per TSRM, if that doesn't fix it check the injector seals. The seals can dry and crack, or could have been installed wrong causing a vacuum leak right at the injector. I have had the same problem as you and it ended up being the injector seals. Good luck.

 

[blue7mgte]

Alright so timing is set per tsrm and even though the check engine light didn't come on it has a code 51 which points to the TPS, and while taking it for a test drive it drove fine for a minute. Then when I really got on it, it began the previous issue, plus I delveloped a freakin radiator leak!! Just my luck lol but once I replace that and the TPS sensor I'll update again, thank you everyone who has contributed thus far.

 

[ifyouaint1sturlast]

I have a 100% brand new Toyota TPS still in the box for 7M. If you're interested let's take this to PM and shoot me an offer. Retail is $99 + S&H.

 

[91supran/a]

while were on the subject im kinda dealing with the same problem just got my car back together after BHG #2 and the car builds boost and wants to pull but feels like my 91na is faster.... no codes checked multiple times. when you try to set timing with jumper in, it jumps around like 3-5 degrees from where your trying to set it. im trying a spare CPS tomorrow and go from there. only other mods are igniter ground and IS300 COP. any other ideas. not trying to thread jack just figured kinda the same problem cept mine does not break up.

 

[blue7mgte]

alright, so radiator replaced and new tps installed, so no more codes. i take it for a test drive after warm up and everything is fine. ten minutes later it starts acting up again,WTF!!!??? but this time i noticed it happens right when i begin to hit 5lbs of boost?? fuel cut off?? when i get home i check the timing again and its reading 0 degrees after its been set to 10, i checked the bolt to see if the cps moved cuz maybe i forgot to tighten the bolt but negative, everything is in place...i wanna take the cps out again and double check everything but til i get a chance does anyone have anymore suggestions?

 

[AJ'S 88NA]

In diag mode the MIL will show code 51 when the gas pedal is slightly pressed and no codes when released. If it does the TPS is set close enough. Never time the engine without first doing this test or at least checking for codes.

 

[radiod]

Also, fuel cut would give you a code 34. If that's not there you can be pretty sure it's not fuel cut.

 

[Crypton2006]

The timing will move around if you don't have the jumper in. The computer is constantly adjusting it, so don't check timing without the jumper in. Let forget about codes for a sec. Try driving your car in a low gear like 1st and see if you can very slowly accelerate to red line without any problems? If so i would bet your have a boost leak. I have had lots of fuel cut with no code 34. Also when your car is running badly is there any smoke coming from the exhause? If so what color? Black? Fuel cut is a VERY different feeling the a misfire. Fuel cut feels like you turn the key off for a second or so then back on..very cut a dry. Miss fire will feel like a stumbling. So what are you feeling a stumbling or fuel cut?

 

[blue7mgte]

awesome advice guys. i do have the jumper in while timing the engine, so im good there. so im crossing off fuel cut cuz its more of a stumble. umm, as for the pedal check(TPS), i am trying that as soon as i get home, then on the road ill do the boost leak check,

thanks.