Hello all.i have a 88 350 which is mated to a 5spd.My problem is the engine just bogs down on accel....fuel psi is at 50 with line disconnected,and the timeing is set to O degs...I then checked for the "hum" from the pump with a key cycle and noticed that the pump sounds sick...it "hums" up and down in random patterns like its being surged..OR not getting enough voltage...I suspect a bad pump OR selenoid.There is no Popping or backfireing on accel either..just lays down.I DID diconnect the relay while running and it stayed running..so that tells me the oil pSI switch is good..correct??? sounds like fuel starvation to me..BUT I could be wrong,any of you guys had the same problem??? looking for some direction to turn next.fustrating as hell this is.i probably won't find the answer myself now for I have "tunnel" vision from being on this problem too long....know what I mean.hope its somehing simple.(do have pump on hand though)


thanks for your time

Brent

 

I assume if it's here it's a TPI. What is the rail pressure if it is revved up and down. Don't overlook a plugged fuel filter. Gas additives are causing more problems than dirt in the system. Based on your description of the problem it does sound like starvation. There are only 3 basic things to look at. Make sure the 12 volts going to the pump is good, and its rare to have a problem because you have 2 paths for voltage as you said. Oil sender and fuel pump relay. Fuel pressure regulator is another. Unfortunately about 8 out of 10 times its the in-tank pump. My first try would be the filter, its easier to replace. You can apply a small amount of vacuum to the regulator and see if the rail pressure varies. Off point here, why 0 degrees? Base timing with EST jumper unplugged should be around 6-8 BTDC or whatever the VECI label states. At 0 even with good fuel pressure it will still run poorly. If you have more info feel free to PM me anytime. Dan

 

Hello Danno..thanks for getting back to me.YES..it is a TPI motor(sorry about that) and the regulator is 6 months old and is checked out good(set @ 50psi ) adjustable one that is.If I had an idea of what is makeing the Pump hum likes its on crack..for those 5 sec's than I could better "home" in on the problem.It probably is the pump..I'm gonna throw in a new relay for the heck of it though.Wonder if its my coil failing me or modual (lack of hot enough spark) hmmmm..that ccoouulldd be it,..no????? The kicker is the 50 psi that its set at.STAYS ay 50 psi when I WOT the throttle by hand(car in neutral)..now the engine doesn't get to WOT like it should..I mean it should "snap" to WOT....but it climbs up to WOT..like I had it on stands in 4th gear ...( a load on it) no what I mean??? theres no black smoke or anything like that.I would think if it was a fuel starvation..the psi would drop...under that load..no???

I set it on O deg's for now..trying to base line it all so i don't burry myself deeper in problems till i find what it going on

hope this info helps your diagnoses

Brent

 

Much better info now. Yes, I would rule out fuel pressure based on what you say. First thing is to set base timing. You MUST disconnect EST connector. It is usually located in front of the heater blower box, it is a single wire with a weatherproof single pin connector. With the engine at temp and running unplug it. You should get a "SES" light or check engine light-that way you know its the right one. Then set base timing, 6BTDC for your engine. Then reconnect the EST bypass wire. If you set timing any other way it won't be right. If it still runs poorly and it revs up slowly don't overlook a plugged catalytic converter. With a plugged exhaust they tend to do just what you are saying. However, you must set the tining correctly to establish a starting point. I'll bet if you unplug the EST with where the timing is running it will probably stall, you may have to advance it some then unplug it so it stays running. Get back with what you find. Dan

 

hello Danno..I must start from the beggining on what i think is causeing this whole problem with no power on accel. I DID set the timeing as you stated.I then rechecked the fuel psi....this is what i found...w/cacuum disconnected---> 50psi Vacuum connected---->42 psi (adjustable regulator btw) I open throttle..either hard or mild (vacuum connected)..psi spikes..but doesn't drop.NOW at idle..it seems to wander +/- 3 psi as the idle moves(slight variations)..so i'm lost there.

I did install a Accell coil (divorced style..2 connector type) and as soon as I went for a test drive..THATS when this all started..NOW I must ask you if theres a way to test this coil..for i believe this coil is not provideing enough sack...though it should..i think its bad. i installed it the way the "stock" coil was installed..i did have to remove the rivets to use the bracket which in circles the coil but it 'bolted up" no problem.Any testes i can do with my volt meter??? AARRGGHH what would you do bud???

thanks for your time

Brent

 

just need some help from last post...new Accel coil and modual..anyone else had this problem when changing the stock ones out??? like i am??? How can i test them to see if the new ones are good???

btw..when i open throttle open..the spark fron the coil (have spark tester hooked in-line to dis cap) dimms a bit...shouldn't it get brighter???.....this why the car "lays down" on accel???

thanks for the help so far....I won't quit on this car..its so simple to repair.. just can't "see it" out of idea's.If it was a clogged cat..would it sometimes "pop" through the TPI when on the throttle??? (heard a pop for the first time today)

 

Been on vaca, sorry for the delay-no laptop. Put the old stuff back in and get rid of the aftermarket ign. You don't need it and you gain nothing. You can measure coil resistance and the main thing is the primary side resistance. Compare it to the old coil. If there is a noticeable difference in the primary side resistance that may be where the problem is. Electronic ign systems are quirkey that way, I have seen it with bikes where the stock coil is expensive and guys use aftermarket. They always seem to have problems unless the coil is model specific.

 

Welcome back Danno!!! (like who wants a vaca to end :>) )

well i checked my timeing and it was off..retarded....and thats how i feel now...I set it a year ago when i put the motor in,and it always ran fine..now the car runs great.thanks for the help on this one.

now the darn primary fan is inop..baught a sensor (temp..in front of intake) see if it kicks her on.have an idea..if i woere to leave the sensor out.. while connected...(antifreez drained of course..and waved a lighter back and forth easy across the temp end of sensor..wouldn't that trip the fan on??? (need to see if I have power to my Primary fan...don't know how else to get both to come on at the same time (A/C is inop....lines need re-seal) or at least check to see if the ECM is sending power to the fan..I'm getting 220-240 before A FAN comes on..which is the passenger one only


Brent

 

Do you know how to run a code retrieval? If not it's here on the site. When you do a code retrieval the primary fan should come on as a self test while the codes are running. Primary should come on at about 220-225, aux fan at 243 degrees. You pulled the CTS, rarely if ever do they develop a problem. I'll bet the primary fan relay went south or typically they get intermittent. You want a quick test, swap the blower motor relay for the primary fan relay. A burnt fan relay is VERY common and can drive you nut's looking for it. NAPA has a better relay for about $19 under thier number AR-279. When you try to run a test tap or bang on the relay with the handle of a screwdriver if the fan is not running, chances are it will give you a clue as to the problem.

 

Hey Danno!

I did replace both relays for the fans..they were put in last week(one right next to radiator..other next to batt).....while doing a code retrieval..the drivers fan does come on..but it won't under engine running conditions....wonder if my ECM is n/g


Brent


thanks again for your on going asistance