Fuel pump? ejswap

[Yo'J]

I took my brat out for a spin yesterday and I have one last issue with it. I noticed that when you drive it to a high rpm and, say, stop at a light, the idle starts to fluctuate and then slowly smooths out. It killed the car twice. It won't do it while driving like a surge or anything, just after reving the motor above 3000-3500. Fluctuation is between 800 and 400 wobbles about four times and then mellows back to normal. Is this a common fuel pump dieing issue? I'm using a larger bodied fuel pump (?) from a spfi or mpfi loyale, used of course.

 

I'm worried it might cause detonation if there isn't enough fuel. The motor is a 90ej22.

[Numbchux]

doesn't sound at all like a fuel pump symptom that I know of.

 

That pump would be plenty of pressure and volume (assuming it's working correctly).

 

 

 

Could be a MAF, PCV valve, IAC or even TPS issue.

[Yo'J]

I'm running two pumps on the same line for a surge tank, would a lack of pump power cause this?

 

Iac was replaced, should work, tps test out, pvc is tested, maf cleaned but I have a spare.

Edited November 30, 2010 by Yo'J

[Subarutex]

Can you draw a diagram of how you have your fuel system routed?

 

It sounds similar to an issue I encounter sometimes. I always thought it was the car running rich because the smaller carb return line can't take the pressure/volume of gas being sent back to the tank.

[rguyver]

its the VSS speed sensor it needs to be hooked up to the dash wiring

[Yo'J]

Subarutex, I'll check to make sure and draw it, give me a day. Rguyver, it should be hooked up fine. I'll double check everything. I'm looking into a garage or I building a tent this week. I'm not getting stranded now. My dd wagon just took a dump too, but one has to run.

[Numbchux]

any CEL codes? if it's a major issue, I think you'd be throwing a code somewhere...

[Yo'J]

I have a knock sensor code, or I did, but I have a brand new knock sensor. I took it to where I bought it from and tested it against another one with a good fluke III meter, tests right on. I haven't gone 100 miles yet in this thing so i'm not sure whats going on. I got brakes and an alignment to do as well, so I havent gone as far as I want to on this swap.

 

Its the symptom that really flusters me.

[GeneralDisorder]

Sounds like you have wireing issues.

 

GD

[Numbchux]

knock sensor bolt torqued to spec? that can cause a bad reading if it's over or under torqued.

[Gloyale]

Rguyver' date=' it [VSS'] should be hooked up fine.

 

Did you make sure to provide a ground to the VSS as well as connecting you're signal wire to it?

 

You have to ground the VSS or it will not make it's pulses.

[Yo'J]

One step at a time, this is my fuel routing every thing else is stock. view surge tank

 

 

I'm gonna pull the dash to double check the wiring. I'll post as I go. I've kept good notes so it shouldn't take to long.

Edited December 1, 2010 by Yo'J

[jrettenmayer]

I've got the same problem with my swap...VSS is hooked up, but I didn't do anything special to ground it. I tapped into the wiring coming from the gauge cluster - I guess I assumed the VSS is grounded through the cluster. How should it be wired up?

[Subarutex]

One step at a time' date=' this is my fuel routing every thing else is stock. view surge tank

 

 

I'm gonna pull the dash to double check the wiring. I'll post as I go. I've kept good notes so it shouldn't take to long.

 

Very cool, thanks for that! I think I would separate the 2 returns, but I don't have a strong reason for this. Looking at the photo of the underside, I can understand why you set it up the way you did.

 

I also only hooked up one wire for my VSS... I thought thats all that was needed?

[Yo'J]

Well I checked everything and It seems ok under the dash. I wired the vss ground through the dash previously and I don't know how well the dash grounds so I re-grounded it just for good measure. My knock sensor wasn't too many ft/lbs over tightened and I havent had a chance to clear the codes, maybe tonight.

[jrettenmayer]

How did you "reground" the VSS?

[Yo'J]

I had originally used a ground on the instrument panel as the ground. I had a few different ground lines set aside for the ecu and other functions, as to not put too many grounds on the same line, I used one of them instead.

[Gloyale]

How did you "reground" the VSS?

 

VSS connector is 2 pin, 2 wire.

 

If you are swapping on a car that already used the VSS, you just need to tap the signal wire.

 

In cars where the VSS was not originally used, and you are tapping into the unused connector, you need to supply the black wire with a ground, and the other (IIRC Yellow/red) get's the VSS wire to the new ECU.

 

For EA81 cars, the VSS connector pigtails right off the back of the dash.

 

For EA82 cars, way, way, up in the drivers side corner of the dash, burried in a cluster, in a 2 wire connector, black, "T" shaped with Y/r and Black wires. It's there for adding cruise to carbed cars. Otherwise on EA82's you can access the wires at the back of the dash, but there you have to cut and splice.

[jrettenmayer]

ever figure out your problem?

[Yo'J]

It still doing the same thing but really intermittently. I have had to do the hg's this weekend on my dd wagon so I havent put much time into it. I was wondering if ground I used from the back of the dash was on or off with the functions of the dash but now I'm not so sure. Being a house carpenter I think of power being on the switch not grounds like in a car. I haven't checked for codes or cleared them or really driven the car. I got to pull the dash again and put in a stereo this week so I'll update.

 

Did your motor start life as an auto? The black wire is what I have grounded but now that I think about it I should make sure that is right.

[jrettenmayer]

Yep...mine is from a '90 automatic lego.

[Yo'J]

Gosh darn year/orientation specific motors! Its hard to swear and make it sound convincing after having to drive it this week. ObII sounds more available moment to moment, though. Just like an extra free 25 horse with a 2.5.