Engine Hunting

[GTUK]

I have today, got my car running, however I have the following problem.

Mods are: HKS VPC with 550cc chip, RC 550s, SAFC2, well those are the ones that I figure will affect running and it seems they are:

I fitted a Walbro, which turns out to be shot, great, since it is a brand new pump, so for the moment I've reverted to stock. I have an Aeromotive AFPR fitted too.

Engine intially ran fine, but now it seems to be running very lean, Wideband monitor showing 14.5-14.6.
Its not been driven so this is measured wth the car stationary.

The strange part is that the engine seems to hunt pretty badly.
If I hold the throttle perhaps 15-20% open (as displayed on SAFC2) it starts to misfire and chucks out loads of fuel smoke, so it would seem to be running way too rich.

I'm certain its a VPC /SAFC2 problem, somwhere in the setup, but does anyone have any other ideas? I'm pretty confused by the whole thing now.

 

[figgie]

well before blaming the electronics... what happens when you turn the S-AFC off?

Have you checked that the TPS is adjusted correctly?

 

[GTUK]

No, not yet, initially it ran fine, wouldn't TPS show up immediately? I'll certainly check it though, good as any place to start. Thanks for the info

 

[Poodles]

How do you know the walbro is shot?

You're basicly using two piggybacks, there was an HKS unit that was supposed to function with the VPC to fine tune it like the SAFC so that might be the issue as well...

 

[figgie]

How do you know the walbro is shot?

You're basicly using two piggybacks, there was an HKS unit that was supposed to function with the VPC to fine tune it like the SAFC so that might be the issue as well...

HKS VPC + HKS FCON + HKS GCC was the package. GCC was the "tuner".

 

[Poodles]

It's been a while since I've read how they worked, but doesn't the VPC mess with the signals to the ECU like the SAFC would and could cause a major conflict?

 

[Rennat]

It's been a while since I've read how they worked, but doesn't the VPC mess with the signals to the ECU like the SAFC would and could cause a major conflict?

yeah, there both fuel controllers... its redundant to run both. i would go with the vpc if you know how to properly tune it. other wise the SAFC is pretty simple too... i would make sure there both zeroed out if your just trying to start it up though.

 

[GTUK]

How do you know the walbro is shot?

You're basicly using two piggybacks, there was an HKS unit that was supposed to function with the VPC to fine tune it like the SAFC so that might be the issue as well...

I dropped the tank, after getting no fuel pressure at the AFPR. The pipe between the pump and feed pipe had dissolved (literally) This was the pipe that was shipped in the Walbro kit. The pump wasn't running when connected, it just kind of clicked and did nothing. Kind of disappointed, since it was a brand new pump, admittedly bought a year or so ago, but I wouldn't expect they have a limited shelflife?

I've read quite a lot that points towards the SAFC working with the VPC, is this not the case?

 

[GTUK]

yeah, there both fuel controllers... its redundant to run both. i would go with the vpc if you know how to properly tune it. other wise the SAFC is pretty simple too... i would make sure there both zeroed out if your just trying to start it up though.

I've removed the SAFC and its making no difference, the reason I went with the VPC was to get rid of the AFM, its sitting with all knobs set to zero

 

[Rennat]

im sure they can work together... but, there doing the same thing, and doesnt the VPC vary depending on the weather too? like hot days vs. cold nights?

the most asked question, throwing any codes?

and you didnt say when you were getting 14.6, but thats fine at an idle...

 

[GTUK]

im sure they can work together... but, there doing the same thing, and doesnt the VPC vary depending on the weather too? like hot days vs. cold nights?

the most asked question, throwing any codes?

and you didnt say when you were getting 14.6, but thats fine at an idle...

going to check codes next, but it was getting dark and working outside is no fun with a flashlight. AFR varies, not much sits around 14-14.6 even when engine revved. Misfire pretty bad, like timing isn't right, this is set to 12 BTDC. Grateful for any help, I'm a bit stumped.

 

[Poodles]

Put it back to the stock 10 BTDC and go from there.

 

[Rennat]

89+ turbo is 12BTDC... EDIT: i looked through his previous threads, he has an 89 turbo... so the 12 is fine.

make sure you have good grounds on the igniter, and the on the coil pack. i made some for my car andjust ran them to the location where the stock battery grounds to he chasis.

 

[GTUK]

89+ turbo is 12BTDC... EDIT: i looked through his previous threads, he has an 89 turbo... so the 12 is fine.

make sure you have good grounds on the igniter, and the on the coil pack. i made some for my car andjust ran them to the location where the stock battery grounds to he chasis.

Ah, thats a good point, the coil pack one is defnitely missing, I didn't pay too much ateention to it, since my UK car runs perfectly OK without it. I'll replace that later.

 

[7MGTEsup]

Ah, thats a good point, the coil pack one is defnitely missing, I didn't pay too much ateention to it, since my UK car runs perfectly OK without it. I'll replace that later.

Your coil pack ground is missing??

 

[Rennat]

Ah, thats a good point, the coil pack one is defnitely missing, I didn't pay too much ateention to it, since my UK car runs perfectly OK without it. I'll replace that later.

i moved my igniter to a lower spot, with less metal contact, and it didnt like it at all. i had a pretty bad miss at an idle... put it back to where it was 'stock' and it idled perfectly just like before. supras are PICKY since there normally 20ish years old... so you have to make sure your grounds are all good and there.

 

[Kai]

Rennat - actually the VPC and the SAFC are two totally different things. The SAFC is a fuel controller, and the VPC is a VEIN PRESSURE CONVERTER that allows you to replace the AFM.

SAFC can be fitted to an engine with either VPC or AFM, and its designed to stop the engine running pig rich.

As for your 12' BTDC answer....erm...sorry to disappoint you, but they were ALWAYS set at 10' BTDC.

Gawain - look on the sticker on the underside of your bonnet, it'll have firing order and timing, i guarantee it'll say 10' BTDC.

 

[figgie]

Rennat - actually the VPC and the SAFC are two totally different things. The SAFC is a fuel controller, and the VPC is a VEIN PRESSURE CONVERTER that allows you to replace the AFM.

SAFC can be fitted to an engine with either VPC or AFM, and its designed to stop the engine running pig rich.

As for your 12' BTDC answer....erm...sorry to disappoint you, but they were ALWAYS set at 10' BTDC.

Gawain - look on the sticker on the underside of your bonnet, it'll have firing order and timing, i guarantee it'll say 10' BTDC.

say what?

the VPC and the S-AFC are the same as they are just doing scaling for what they were programmed (VPC+550 chip) or adjusted to (S-AFC). Both are tricking the ECU and not taking over the fueling directly.

btw Even though the answer you gave is correct, the answer is inside the tsrm

http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=IG&P=20

and specifically

10 degree with Te1 and E1 shorted. 12 degree or more without the jumper.

 

[GTUK]

Right, some more info.

Checked timing, spot on, 10deg with TE1/E1 bridged.
Checked ECU codes, only get code 31. Does this indicate something?

Wastegate seems pretty well jammed shut, so thats next on the hitlist.

Oil Pressure gauge doesn't seem to display anything, I think its the sender, how do I test that? Also its a digidash car, I believe the sender is different, so don't have a spare. Does anyone have the part number for the correct item?

Temperature gauge is showing half, as soon as car started, earth or sensor?

On the other hand the Mishimoto rad and fan package are awesome

 

[Rennat]

the only 'advantage' to the VPC is that it deletes the stock AFM... i personally like SAFC's over VPC's only because of how much more tuning the SAFC2 has in it, and now the neo has like 32 different rpm settings?


and as far as the timing thing goes, you should check out the TSRM befor you dispute facts that i've put up.

FYI - under my hood, a 1990, it says 10BTDC WITH the connector jumped. if you actually go read my post i never say anything about the jumper...


GTUK - did you ever try to unplug the SFAC? and where is your wideband o2 placed in the exhaust stream?