Do I need a fuel pump..or something else.please help..

[DSM'r MOM]

Ok I can't figure out my problem, and ether can any mechanic around here. I decided to drive it to work today (about a 30mile drive) big mistake. It dies about 10 times up there. Always when I stopped or braked fast. Also it was cutting out or stuttering or missing. at any speed. At 60 in cruse it would stutter and a miss a bit, also down a hill it would do it. I finally get it to work, but it dies after I start it up again my temp Gage is sky rocketing. It reads 262 or so ,but not gage light comes on and it didn't show any signs of over heating like blowing a hose of or something. Anyway I shut it off and start to panic I feel the worse after all the work I have done to it. I do a compression check and it checks out ok 150, 150,155,155. But I look at the plugs ...there very white, which is lean, but still not sure.

Luckily I'm at work were we have any tool we need (I work at a go kart shop) I decide to test the fuel pressure. It reads 35 with the vac connected, now my question is. Is that ok if it's a few psi low? I know it's supposed to be like 37.5 or so. On a 1g anyway. I'm planning to order a new pump tonight anyway, because I need it for my turbo, but I don't know if thats my problem, Also on the logger it reads like.10-.13 and hardly moves at all, but usually that will throw a code if the O2 is bad Right? It is old, but could it cause this. The car will only boost to 8psi. And the turbo has like maybe 80miles on it now. Oh yeah no boost leaks. Also I tested the pressure at the fuel filter with a universal mac fuel gage.

Also could it be the coolent temp sensor, since it really didn't look like it overheated, or maybe the reason it did was because it was running to lean. Also those O2 readings are at idle, no load. so is the fuel pressure.

I need help bad and a direction to go in.

so I think this is whats causing it..if you think of somethings else just add

1.fuel pump
2.timing
3.cat
4.injectors (all of them)
5.coolent sensor
6.O2sensor
7.?
8.?


I would rather replace one than all of these, if you look at my other post you will see all I have replaced

thanks for the help DSMr Son

 

[fishtank]

A couple questions first.
1) Is the car stock or have you done any mods to it yet.
2) Does the car idle at all by itself or does it just stutter and die
3) was the car in open or closed loop when you were watching the o2 voltages

From what you have said in your post about off throttle stuttering and stopping it sounds like you do have a boost leak of some sort. At the very least test it again its one of the easier things to rule out. And then move on from there.

 

[DSM'r MOM]

The car is completely stock except a evo turbo, a evo manifold, and balance shaft belt removed.

It will hold 15psi for about 30seconds and bleed down, I did have 2 leaks but fixed them both, Also it will idle sometimes around 300-500 sometimes a bit higher, but usually it dies. It has just started doing this, before it would at least idle

sounds dumb, but how do you tell if it's in closed or open loop?

Also is 35psi with vac on to low for pressure?

I'm ordering a 190 fuel pump and gage for it right now, I would get a 255, but don't have the money to install a AFPR



thanks DSMr Son

 

[knighteclipse1]

o.k....first off...is this a first gen or second gen car? Probably wasn't the best use of your money to start with a turbo upgrade and not prepare for the upgrade ie; exhaust,downpipe, fuel management fuel injectors and the like. the factory intercooler isn't able to take full advantage of what that turbo is capable of, kinda like going to a gun fight with no bullets . we need you to fill out your vehicle profile to better help you. I know it is frustrating when you vehicle isn't running properly, we can help you better if we have as much information on your vehicle as possible.

 

[Spoolin4Ever]

Yes, what car is this? It's a 1G, but which year? What tranny?

Just tell us what was replaced, I don't wanna hunt your other thread down.

 

[DSM'r MOM]

Ok first I know all about the supporting mods, I only replaced the turbo,because I thought it was the problem. It did have a huge crack in the waste gate.
It's a 1990 GSX Black AWD Turbo..... It has 118,000 on the engine the head was replaced about 3-4,000 miles ago. The timing belt broke. I replaced the head, exhaust manifold with a evo, arp head studs, belt, auto tensioner,both pulleys,took the balance shaft belt off, all the top end gaskets, plugged the egt bung until I get a EGT gage.Replaced the fuel filter with new one, replaced spark plugs 4times and wires twice (first set was very bad quality) Replaced the O2 with a known good one, Replaced the tb with one from my parts car. cleaned it out before installing, Replaced coils with known good ones, gapped spark plugs to .28 or .028 whichever it is. Changed oil and all fluids except coolent, just added a little to that. Will flush out this week though. New t-stat, new rad cap, new evo turbo.

thats about it everything else is stock, once I figure this out I plan to put an exhaust on it. And a k&n air filter. I'm just trying to get it to run right thats all. I know to wait to turn the boost up, but 8psi seems a bit low, and it just doesn't sound right when it gets up there. No one around here knows anything about these cars. I have done it all myself. I have owned three a talon 1990 AWD Turbo Auto, and a Laser Turbo FWD, and this one.

I will fill out my profile, but I have said it all right here.

It's a 1g is my fuel pressure below standards since it's supposed to be 37.5 with vac on and mines 35??

How much does the fuel pressure have to be off to cause problems???

I just ordered a fuel pump even if it's not my problem, because I need it anyway for my turbo. I know it wasn't the best thing to replace first, but when you have replaced almost anything else it's one you have to try.

One more thing I have a logger if you want any values at all, I just can't do WOT because I don't want to push it the way it's running, I wish I had it on when I took it to work, I bet it was knocking. Also the tps is reading 12.9 at idle, isn't it supposed to be like 9% or so? And my o2 at idle so I think thats closed loop is reading very low, and freezes sometimes, Could my faulty turbo have damage the O2? And when I had 2 huge boost leaks it never blew black smoke so I think it has been running very lean for quite a while, but compression checks out.

thanks DSMr Son

 

[DSM'r MOM]

Sorry one more thing, could my coolent sensor be at fault, no codes have been shown so far except 12 ad 41 which were for fuel injector harness and MAS which I unplugged both one time to try and see what it would do.

Anyway my coolent temp read 260 degrees, and it showed no signs of really being that high which maybe means my coolent sensor is faulty

thanks DSMr Son

 

[knighteclipse1]

you say that you don't go past 8 psi boost, hhmm....manual or electric boost controler? Sorry about not noticing that you had a first gen earlier, my bad. I assume your not having the CEL going off. Not meaning to question your mechanic skills or anything, but have you checked your timing since you put on the belt? Where were the boost leaks coming from that you fixed?

 

[DSM'r MOM]

thats just it, I have no boost controller yet, I thought stock psi was 9-10psi? But even though it boosts that much it's not running right. The boost leaks were from the j-pipe, It was bent (the surface wasn't flat) and a vac line going to the t-stat housing. Before I fixed the vac line tear it wouldn't build even 5psi, after that it would build 15psi but bleed down very fast, after the second one (the j-pipe) it holds for about 30 or so seconds at 15psi and bleeds down slowly.

The weird part is, it ran better with the boost leaks WTF

All signs are pointing to fuel problem, or some restriction in the exhaust.

No I haven't checked timing, I have checked the top cover and they line up, but that don't mean much when I don't look at all the marks It's a very big pain to get to so I'd rather count that as being ok. My timing it's self ignition timing seems to be at 5degrees so that checks out for now, It just seems not enough fuel. All of the plugs were some what white, thats why I need to know if my fuel pressure is low enough to cause trouble?

I took out the stock pump tonight, having problems getting the screw off, in a few days I will receive the new pump from slow boy. I hope it solves the problem, if not I don't know what to do next. Also what if one of the nuts break that surround the top of the fuel pump assembly, I broke one, but the other five are fine, how do I fix that?

I guess I will try and check the timing after the pump if that doesn't help, but it will run good sometimes and then bad for a while and good again, I don't think timing would jump and then realign it's self

Lately though it has been worse, won't even idle now and I haven't drove it since it over heated, I wonder if I didn't get enough coolent in after the turbo install. It just seems after the turbo install and fixing the boost leaks it has got worse.

If this doesn't work, I guess injectors are next, but this is getting costly I would rather spend my money on a water oil and egt gage or some mods like a K&N or exhaust

thanks Derek AKA DSMr Son

 

[knighteclipse1]

if you have a local mitsubishi dealership near by, you may try to have them diagnose the problem for you and you could fix it yourself, after you know whats wrong...might end up cheaper to do that then to keep replacing parts that don't need replacing at this moment. Seems like you have most of your bases covered. I was hoping i could help, but now you have me stumped WTF

 

[DSM'r MOM]

there is not dealer with in 100miles of me that knows anything, plus wen I take it there they will probly charge 50-100 to pullcodes ad what not which I can do with my logger. It's no use think I may just wiat til I get to UTI and see what happens

I just need a solid anwser Is 35psi to low of pressure with vac line on??

thanks Derek

 

[knighteclipse1]

well, i can't speak for the exacts on a first gen car, but my second gen fuel preasure should be between 46 to 49 psi. I would assume (ass-u-me) that the 1st gen would be similar since power output is very similar from the factory. 1) fuel filter clogged and/or impurities in the fuel system. 2) Low fuel output at the injectors (first try cleaning the injectors) 3)faulty or incorrectly gapped spark plugs 4) Faulty emission system compontents. 7) low or uneven cylinder compression preasures 5)weak or faulty ignition system 8)vacuum leaks. these are the steps that Haynes repair manual shows to follow, since you have done some of the footwork already. just process of elimination hopefully will get you to the results you want. good luck dude. let us know what happens.

 

[93ESTalon]

According to vfaq, your fuel pressure should be 36-38 psi with the fuel pressure regulator vacuum hose disconnected and plugged. With everything connected it should be 27psi (stock). These spec's are for a 1g Turbo only. Hope that helps.

Tyler