Purple 92 SS

Ok, so im fairly new to fuel injection TPI cars. I've only had this one for about a year, and havent had to really do much work on it TPI wise... I dont know much about TPI cars at all, as my others were either TBI or carbed.. so please bear with me and see if you TPI guru's could figure some of this out.

About a month ago i decided to recharge the AC. I got it recharged, and while running it got up to about 230' on the temp guage, and started stumbling. This is at idle. What I mean by stumbling, is the motor began all out of the blue to start having issues running, almost like it was loaded up with fuel, or couldnt breathe.. My mechanic friend (30+ year ASE certified) and i thought that my Catalytic was clogged. well, long story short, I replaced the Cat with an Off road pipe, and thought my issue was fixed.

it wasn't. The car this time, wasnt that hot at all(comparitively to what ive been told its supposed to run at), maybe 200-210 roughly on factory guage, and started the same thing, wouldnt run, wouldnt do anything under its own power, stumbling like its about to stall, and eventually stalls out and wont run until its sat for hours... A friend of mine (who has had numerous tpi cars) thought it was the ICM (ignition control Module) on the distributor. so i bought one of them, and replaced it. (i also tested the origional, and advance auto said it was good but i replaced it anyways) So i thought that fixed my issue as well. It didnt.

Another friend suggested fuel filter getting clogged, as it *MAY* have debris being sucked up only when driven (hence the randomness of the issues) SO i changed that as well. This time, the car was getting hot again around 220ish, and it started stumbling again, almost like its loading up with fuel, but im not 100% positive it is.


It only seems to do it sometimes, very randomly. What could be causing this? Would I be right thinking i need an adjustable Fuel Pressure regulator? I havent measured the Fuel pressure yet at all, but I did replace the fuel pump about 5 months ago. This problem has only developed in the past month or so. I know the car has an SES light thrown every so often, that has to do with EGR, but I dont think this would be causing it as it's thrown the code for EGR in the past numerous times, way before the new fuel pump, or this new issue, without issues. So I'm at a loss as to what could be the problem. I dont want to keep throwing parts at it, as im not made of money, but I do want to fix it right, as it is usually my daily driver car.



here's what the car has :

De-Smogged
No catalytic Converter
TSP Exhaust
BBK 255lph Fuel Pump
New fuel filter
K&N Air Filters
Throttle Body air Foil.


Thanks in advance for any ideas and help, as im at a loss on this issue.

APACHE JOHN

Check the coolant tempature sensor.....

Purple 92 SS

ok, i can check it but how would that effect the car from running? Im a bit confused. thanks again!

stealth908

iTrader: (2)

Do the drivability problems only happen when the engine is warmed up?

Get the cooling system up to par first. Have the radiator cleaned. Replace the thermostat, and put new coolant in it. Make sure your fans are coming on when they should. I believe the second fan should come on when the temperature reaches 220, or when the A/C is on.

Pull those codes from the computer. Then check your fuel pressure. 43 psi with the vacuum line off, and plugged. Then check for vacuum leaks (vacuum lines and gaskets).

Check the coolant temperature sensor too. Just change it.
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The CTS tells the computer what temperature the engine is at. The computer will adjust the fuel curve to compensate for the temperature of the engine. If the engine is hot, and the sensor tells the computer that the engine is cold, then the computer will probably be trying to keep the mixture rich.

Purple 92 SS

Yes, the drivability problems only happen once vehicle is warmed up, but they do NOT always happen. it seems to have no rhyme or reason for it, and frankly it makes me nervous to drive the car anywhere, because i dont want to be paying for a towing bill.

Cooling system seems to be fine, I've used a digital infrared thermometer on the motor and i havent noticed any great variation on the temperatures, and definately never getting hot enough to cause damage. The second fan does come on when it gets hot enough, and does definately funciton when AC is charged and on. The primary fan does also work without issue as well.

I'll check codes next time i get the light on, but its not often. As for FP, ill have to check that as soon as i can get a chance to do so.

The coolant temp sensor is the one on the top of the intake correct?

stealth908

iTrader: (2)

You can pull the codes now. The computer will store codes in it's memory for soem time. Not forever, but for a little while. Just use a paper clip and count the flashes of the SES light. This gives you the code #. If it's stored, the code will show up.

I'd atleast flush and fill with new coolant. If you are seeing hot temperature on the gauge it's either a cooling issue that needs to be addressed, or the gauge isn't accurate. Flush and fill is cheap. Basically don't count on the gauge being wrong.

Yes, the CTS is on top of the intake below the throttle body. There should be 2 wires coming off of it.
http://autorepair.about.com/library/images/bl210lib.htm

Purple 92 SS

I've actually got an OBD1 reader, but have done the paperclip trick before as well.


i'll flush and fill myself, as last time i took a car to the dealer for that was 150.00 and thats not fun. lol.

Ok, ill replace the coolant temp sensor. thats a no brainer then.
Thanks for the ideas, and also the help in telling me what the CTS controls like that. I had no idea that it did any of that other than say how hot it was actually. thas wild.

Im planning on also replacing the fan temp switch, with a 185' one instead of the factory temp one.

three-z

test you injectors if they are not working properly they can make engine run lean therefor over heat

Purple 92 SS

i've replaced the coolant temp sensor, and while i was at it i bypassed the Throttle body heating hoses too lol.

i havent noticed the issue to recur as of yet, but have been largely unable to drive the car, as there is now something wrong with the driver window motor/lift setup. SO i have to fix that as soon as we get some decent weather. I also topped off all coolant fluids, and at this time it appears to be fine coolant wise. the car does cycle normally, and the coolant fan kicks on around 230 ish on the guage, and cools down to 220 without issue. under driving, the car cools down to 160-180ish, but in traffic/idle 220 when fan is off and returns to it when fan cycle is done. only the left(driver side) fan comes on. the AC system, has leaked the coolant out again, and fails to cycle on, thus the right fan fails to kick on when the ac is engaged, and i assume it never gets hot enough to kick on without the ac being engaged. It *DID* kick on when the Ac system was charged and was engged in last month.

Rich2279

iTrader: (7)

As for checking the fuel pressure, there is a port on the fuel rail, which makes hooking up a gauge and checking, easy. This is just a tip I'm not suggesting this is or is not a fuel issue.

Purple 92 SS

Yea, Im planning on checking that, but havnet yet. I hope to get some time with her tonight, but the weather is beginning to make me think i wont be able to work on it at all today. (rain forecast) I am pretty sure its not a lack of fuel presure, but the "loading" up sound/feel of it may mean the Factory FPR is toast.. im not sure.. i'll let you guys know what i find out.

Purple 92 SS

well i drove her to work today, no issues. This is after having her at idle for alot of time this past weekend, with no issues. The real test i think will be coming home tonight, to see if she "loads" on the way home. im trying to not be too gentle with her either, as i think it was acting up when i was a little hard on her.. so we'll see.

I still havent had time to meter the fuel pressure.

Purple 92 SS

drove her to work all week and on the way home yesterday she re-manifested the issues again. I dont get it. I really need to check fuel pressure, but it seems so random.. drives fine 2 days and then self destructs when im almost home on the third day. I dont get it. Especially since there is no codes being thrown.. its so odd.

APACHE JOHN

No codes? don't have a spare ECM to try do you?

irocuroc

sounds like mutec failure like everyone else.. ohm check the inhectors and post the results. warm up the engine and test each one. if any are under 10 ohms. There is your problem

Purple 92 SS

nope, no codes, and unfortunately no spare ecm. ;(

Mutec failure?? what is this?

How does one check the ohm's of the injectors? i have a multimeter, but other than that, im new to it. Is it something i can do when the car is running?

irocuroc

here ya go
http://www.youtube.com/watch?v=_g8PdrT0MCU

86firebird350

Still having this problem Purple?

What size and brand fuel pump did you replace the stocker with?

Purple 92 SS

yar, i put a bbk 255lph in (which is nothing more than a walboro makreted by bbk)

86firebird350

you might try posting this on SCFBA. i believe charles and travis have both had issues with a fuel line after replacing the fuel pump. im not sure exactly what it was, thats why i say post on SCFBA.

Purple 92 SS

i'll post a hot link to this on there.. too much to retype. lol.

-steve

gm4lyfe

Ok, so I'm new to this web sight but I'm not new to thirdgens. It really sounds like your fuel pump is slowly failling. What tends to happend is that as the pump heats up, it slowly starts to drop in fuel pressure which causes the motor to run lean which can cause temps to rise 10-20 degrees. that would explain why the car runs fine and then suddenly just starts wanting to stall out. What sucks is that not all pumps "just go", some take thier sweet time. But as they get worse you get less and less time till it just leaves you stranded. And checking the fuel pressure at idle can be misleading, if the pump is bad try test the pressure with 1/4 tank of gas, and after letting the car run for at least an hour. And don't just start it up, rev it up too, put some stress on the engine and see if the pressure stay solid or tends to drop rapidly. Sorry to say this but don't count on that walbro pump just because it isn't that old, in another message board guys were saying theres were going within 6 months. One more peace of advise, running lean can foul your plugs up so make sure you take a look at them, they may need to be replacd.

Hope you find the cause and fix it.