Good Morning Group! Newby here, please be gentle..

This is not an 'F' body rig, but the power plant is, I hope I do not offend anyone. Of the sites I have read, it would seem you guys have a lot of knowledge with TPI so I thought I would throw this out there.

I have a rock buggy(custom tube chassis with hand built body) with a 350 TPI/700R4/4.56's with 37" tall tires. I have it at the mechanic's shop now because the power just didnt seem up to snuff for what is in there. I have only owned this since August, and it has been running the same since I bought it.

Where the problem really shows up is when highway driving, like up Cajon Pass(5-6%) it will only hold 60 mph. It does fine at low RPM like when rock crawling, but it does die after slowing on compression for awhile. This really gets your attention when coming down a mountain road and all of a sudden you have no power steering and find yourself trying to armstrong 37" tires!

The engine was a new crate engine in 2000, the TPI was a used special, and the mechanic is telling me that he cannot do anything without finding out everything up to and including the VIN that the TPI came from. He said it has the MAPP sensor, so he narrowed the year of the computer and TPI down to 90-92. But untill he has the specs for the crate motor(valve size, etc.) he cant really do anything with this. (I have since supplied him with the Chevy part number of 10067353 that was purchased in April 2000)

He says that the engine is running out of fuel, even tho the fuel pressure is 45 lbs at full throttle per spec. He also says that the injectors are not staying open long enough to give it the fuel it requires, but says he cannot adjust them without knowing the above information.

Is this guy full of it or am I being an ignorant a$$? If I dont know something I am the first to admit it, but something isn't adding up my gut feeling tells me.

Thanks for your opinion, good or bad!
John

 

Doesn;t sound liek B.S . But that 60 mph cutoff is wierd . what cam and all that stuff is in the motor. The TPI doesn't like big duration numbers .

 

cam is .390"/.410" lift, Duration at .050":195 degree / 202 degree.

The mech is claiming now that thie TPI unit has Ford injectors installed. Aren't injector made by bosche or whomever, or are they stamped somesuch?

Man I hate being ignorant!

Thanks, John

 

The for injectors are rated at a different PSI . You may have a rich conditon . Like the 19 lb ones may more be like 21 lb's . you got an A/F meter on it ?

 

His diagnosis has been that it is running out of fuel(lean?) and that is why I run out of snort going up the hill.

This buggy is usually trailered everywhere and just runs off road.

I know basically nothing about this sort of fuel injection, I can see now that an education is in order. I dislike being ignorant!

Thanks fr your help. John

 

yeah there shouldn't be a problem with the ford injectors. I have 23 lb ford injectors in my tpi setup. they were alot cheaper then bosche, accel and gm injectors. But I think D's89IROCZ is right about them being measured on a different scale. I also think the mechanic might be right. Oh and the amount of stuff you can learn off this site is amazing. I've been working on these cars for 6 years and everything you ever need to know about TPI can be found in this forum. Just do alittle search, someone is bound to have had the same problem before.