I've got a sprint re and an 88 tII.
I'm getting a lean condition with quick throttle at boost. Vacuum isn't a problem and boosting with very little throttle is not a problem, but when I give it quick throttle, once it gets to 0 psi it immediately goes lean.

Can someone point me in the right direction? Im no00t sure which map I should be checking.

 

S4 TPS? If yes, that's your issue.

 

Y, its an s4 tps. What exactly is the problem?

 

The S4 TPS is basically an on/off switch. It's not a linear, full range sensor and the signal the ECU receives doesn't properly correspond to actual throttle position. So the transient throttle function doesn't work properly and you get lean or rich spikes when the throttle is rapidly applied.

Two choices to fix it. One, swap an S5 throttle body and TPS on to your engine. You need both as a pair. The S5 has a full range sensor. Or we have a kit that converts the S4 TPS in to a full range combo. It repositions the sensor and includes a cam wheel that slides on the throttle shaft to actuate the sensor. The kit requires removal of the oil metering arm, so premixing is required. PM me for more details.

 

pm'd.

 

Replied. Sorry for the delay.

 

I haven't received the kit yet, but will be installing it as soon as it comes in.

Thought, now it seems that even when giving slower throttle input, it'll go lean(feels like fuel cut) once it goes over 0psi. Makes me wonder if something else could be going on.
I disabled the over-boost fuel cut via the Haltech software to see if that would help, but it didn't.

 

Staging issue?

 

Using the sprint re, does it stage the secondaries based on boost pressure instead of or in addition to rpm?

 

I found the staging section of the fuel setup. I'll do some investigation.

 

MAP only.

 

I had someone from Haltech tech support remote in and make sure the ecu is setup correctly.
I checked the secondary injectors individually by applying power and ground leads and listening for it to click on. They both are working.

Is there anything that I may have missed? Something else to check?

 

Email me your map and get some datalogs of what it's doing and send those as well. chris@lms-efi.com

 

Maps and datalog sent.

 

If the ECU has a way to do accel fuel based on Delta MAP you can tune it that way and have pretty good success. Unfortunately the Sprint RE does not so changing to a linear TPS is the only way to go here.

EB Turbo

 

Here are the maps and datalog in case anyone else has any ideas.

 

1. Change your Staging Load in Setup to 1.5 not 2.0.
2. Make your Staging Bar Injection Time the average between 1.5 & 1.6. maybe higher if still lean.
3. Delete column 1. Lower that value to your lowest vacuum reading. Looks like -25. Add a column in Fuel Base at 1.4psi. Make the values the same as your 1.5 column.

Proceed with caution, I'm not a tuner however my map is set up in this format and works fine.

Perhaps C. Ludwig could confirm my analogy.

 

Thanks. I'll give the above a shot.

Question..since it goes way lean at almost exactly 0psi, is there anything else in the ecu setup outside of staging that could cause this?
The more I think of it, the more it seems like some sort of fuel cut.
The afr's are good all the way up to 0 psi. Tthe ratio immediately jumps to 22:1 at almost exactly 0psi.
If it was just the secondaries not firing, wouldn't there be a more gradual rise in afr's being that the primaries are still firing at 0psi?

 

I sent you an email with a modified map. Give it a try. You're close to having it setup correctly but have a value for staging bar in the fuel setup screen that is incorrect for the way base fuel map is structured. The result is the ECU fighting itself. No reason to make big wholesale changes.

 

Wow.
I imported your changes and problem solved. Good afr's all the way thru boost. Drives great!
Thanks for all your help!!