smokingss

ok, i'll first give a basic rundown of my setup,
350 block, rebuilt, original bore
92 tpi SD runners, fuel rail and manifold,
88 tpi plenum and throttle body
730 ecm with custom chip to remove vats
full length 3" headers, dual cats, dual 3" mufflers.
K&N filter on throttle body
T5 manual trans
air select and divert valves removed, purge and egr still intact.

ok now for the problem, the car starts up fine and idles great, however at just about 3k rpms, the engine breaks up and doesnt want to rev over that. I have a feeling it is the timing, i installed the distributor and never got to do a timing check yet, hehe, i will this weekend. but i want to see what else it could be so i can check all the possibilities this weekend, I was also told to check fuel pressure. it has a in tank tpi pump from a 88 305 tpi iroc. what should the pressure be at idle and say at higher rpms? what else could i check to try to diagnose this? I appreciate any help. Thanks in advance. -paul

KiLLJ0Y

i had the same problem, mine was the fuel pump.. wasnt supplying enough.

did you convert this from a TBI or some other kind of engine? have you changed your fuel filter?

smokingss

I installed a new fuel filter and a used pump from an 88 iroc i parted out. the iroc ran so im pretty sure the pump was fine, i put a new sock filter on the pump as well. I could possibly still have fuel starvation. i did a carb to tpi conversion, but its not an fbody, its in my 87 monte ss. I installed a grand national tank, tbi monte sender and pump hanger, and the iroc pump. i also ran 6AN line 50% or the way and used about 50% of the stock hard metal 3/8" feed line. the return line which was 1/4" i swapped with the vent line which is 5/16" and made the old return the new vent line. I have 97 lt1 injectors as well i fogot to add. I may have restriction in the fuel line to the fuel rail that whay i need to check fuel pressure, i think i remember hearing psi for tpi should be around 47, does anyone know if thats correct? is that just at idle?

/\/3\/\/l8l3

check your injectors, is it knocking or rattling your tach past 2500?

smokingss

the injectors were said to only have about 17k miles on them, and the tach reads fine right up until it breaks up at like 3k. Its an autometer tach. the engine feels like it just cuts out at 3k rpms. liek i said, i have no idea where the timing is set right now so that could be it.

KiLLJ0Y

if the engine is cutting out then comming back on... you have a fuel problem. check the timing, but you are having the same problem i did.. i was using a brand new walbro 255 and the damn sock got sucked into the pump.. making it only pump very little, but if you needed more about 3500, forget it.. it would shake and stuble until i let off.

i switched to a brand new LT1 pump which is double the rating of the TPI.

now you said you went to 24#'s have you burned a new chip at all for the new injectors? you need to.

is the engine give any codes at all?

smokingss

i had the chip burned when i bought the custom harness(reworked 92 harness for stand alone) That was back in april. i just finished assembly last month and I honestly cant remember if he had it programed for the lt1 injectors. and now that you mention it, i dont think so. the ses light is on but i havent been able to scan it yet, and i'm to lazy to jump the pins to get the light to flash the codes, lol. If anyone is in the north jersey area and would like to help me with this, id appreciate it. Also, if someone can burn me a new chip set up for everything done, i'll pay whatever it costs. As i was thinking about it, i also may be outta gas LMAO , its a brand new tank and i just put in like 3 gallons, if that, and with the sump type thing in the grand nat tank the pump may not be gettign enough, so first i'll fill the tank more, then ill check the timing, then fuel pressure. after all that i'll start looking into the codes and such. but thanks for all the advice so far, keep it coming, i can never have too mcuh help.

KiLLJ0Y

get a paper clip and check the codes 1st before you do anything else. you might be damaging something that you may not know by driving it.

pull the codes, then do the rest. remember to rest the computer once you pull the codes (unplug the negative bat cable for about 30 sec to rest)

Morley

Is it worse when the engine is warm vs cold? If so: Check the coolant temp sensor....

TPI Monte SS

Hey Paul,
It might also be the ignition module. The one in my TPI Monte croaked a while back; not enough dielectric grease between the base and module. Had the same symptoms you're describing, but got a code with it as well. Got a spare you can swap in and test it out with?

scooted45

I had the same problem once because I hooked up some vaccum lines wrong. Just a thought

smokingss

the ignition module is pretty new, maybe 30 min of run time on it total. the distributor itself could possibly be bad, its from the 88 iroc i parted out and i wasnt 100% positive it was good.

it could be the vacumm lines now that you mention it, switching into the g body required running all the hoses custom and maybe i missed something. ill recheck it all and i'll also try another map sensor just in case.

smokingss

ok, first off i'd like to thank everyone that has offered advice, i guess some message boards are helpful. I appreciate it. ok back to my point. Today I finally got a chance to look at the car and I think if ound the problem. I will also state right now that i am a complete jackass. The problem has seemed to get worse over the past few days. i popped the hood and decided just to check the plug wires on the distributor to make sure they werent loose or arcing through the stainless steel braided sleeves. they were all tight on and grounded correctly on each side, so then i happened to grab the distributor and it wiggled a little, i looked at the base and that was tight, it was the cap that wasnt on all the way. right then i felt like an idiot. i looked at the hold down screw and that was tight, so why was it loose? well it helps to actually put both screws in and not have the whole cap off set from the rotor. i couldnt believe i made this mistake. i pulled the cap and the inside was all marked up, plastic debris all over and the rotor well that was bad too. so... i'm goign now to pick up a new cap and rotor from my old shop and try that, hopefully thats all it was. And i think everyone will agree with me that most liekly that was the cause of it breaking up, after all half the engine wouldn get spark since the rotor couldnt reach the inside terminals and instead was cutting into the wall of the cap on the other side.... so yes, i admit it was a very very dumb mistake but at least if it is that, its easily fixed... wish me luck i'll let you know how it goes....

smokingss

ok, so that wasnt it...i really cant see how the wasted cap and rotor didnt really do much, anyway, i got the new cap and rotor in and tried it, same thing breaking up at 3k rpms, i dont have a timing light right now, so i just tried turning the distributor a little to see if i got any change. i moved it a little then started the car again, this time it will rev up to like 4100rpms, so now im convinced its a timing issue. next step is to get a timing light on it and see exactly what im working with....

conlinj

iTrader: (3)

did you just put the motor together? you might have the cam timing off, i put the chain on the wrong keyway on the crank, car did the same thing wouldn't go over 3K

Just a thought...

smokingss

yes i did just put the engine together, but i was very careful with the cam and timing gears install. i am 95% sure its right, but theres the 5% that says anything can happen, so if i cant correct it once i get a timing gun on it, i guess thatll be my next step, to rip apart the front of the motor and check that... evil car, evil evil car...

Red Devil

What did you use for goop on the back of the ignition module?

smokingss

the ignition module came with dielectric grease which i used. i put the module in back when the entire tpi setup was in the iroc, which was running at the time i pulled the engine.

also, what should the stock timing be set at?

Red Devil

Not regular clear dielectric grease, but the thermal white goop, right? ---(Wells part no. SL203) ---

The clear stuff, IIRC silicone dielectric grease, has been reported to have problems dissipating heat. IIRC dielectric grease isn't the *best* conductor either.

It keeps moisture out of connections when used on both spark plugs and regular low voltage connections. When you use DG in a connection and slide or bolt the connectors together you make a metal to metal contact that carries the current.

The DG seals out air and moisture at these contact points which prevents corrosion.

There has been rumblings on the Ford boards that Ford issued a memo to the service dept.s that dielectric grease is not to be used in place of thermal heatsink compound on the TFI modules. (Probably because of problems it's had... with heat).

If you used the clear stuff, I'd get the module tested.

smokingss

check my new post please...the ecm threw code 51(bad prom or ecm)...ugh

RMC030

My friend you and I have the same issue!!! I have been chasing the same problem for the past 3 months. Fuel pressure drops to 10lbs when the car is warmed up and runs bad. When it's cold no problem. I have replaced everything under the sun in this car and it still is not right. My next step is to check if the voltage drops at the pump during the problem. I replaced the pump twice. I really don't want to drop the tank yet!! To be continued...................................

smokingss

i think i have it all fixed now, this is a copy of the post i just made under my other topic (code 51...now what...) i had the rev issue before i found out about the ecm 51 code, and they may have been seperate issues, but i think it was mainly just the ECM. (if they were seperate, then i must have just had the timing off)

"ok well i finally got time to get back to the car today, i reconnected the + battery teminal, got in turned the key, "vrooommm" started right up, idling very nice at like 1200, it was ice cold and i think i turned the idle up last week, but smooth. It didnt even smoke really like it did last week. i let it run a few seconds, its still not full with cooloant(since i was maybe pulling the timing cover) after like 10 seconds, i gave the gas pedal a little stab, it easily shot the tach up to 4500-4700 rpms solidly. And the SES lights is off and stayed off. so all in all i think i figured out the issue it had. apparently the ECM was bad and messed everything up since thats all i changed(other than correctly setting the base timing ) but the SES light now is fine and i dont think bad timing would have set a code 51. Tomorrow the car is getting registered and insured, then i can test it on the road and fine tune it from there....."

conlinj

iTrader: (3)

kewl, glad to know it's running good