New owner from WI.

[Choptop]

Had a '61 for 10 years, back in the 70's, bought an '89 convertible last Nov. Spent the winter replacing things, because it's 37 years old and a pathetic Carfax. It is a good example of a fairly well taken care of car w/decent original paint and no apparent accidents. Am used to old school, carburetor/air/ignition, this TP! has me scratching my 75 year old head but I am learning. I drove it over an hour home after purchase, then it went directly in the garage, over the last month I have replaced the injectors w/Bosch111's, replaced the fuel pump, new filter and new diaphragm in the fpr and I am only getting 30# of fuel pressure, starts hard and is a dog. This weekend I put the old fuel pump back in, installed a new diaphragm, their appeared to be nothing wrong w/the old one, and I still get only 30#. After I prime the lines, w/30# it doesn't all bleed off like I see some video's, after 10 minutes I lose about 5#'s. Love the car but am not enjoying driving it, any suggestions? Thanks in advance.

 

[Tom Bryant]

Welcome to the CAC.

Share your problem in the C4 Forum and you should get some good responses. More than likely someone has been through this before.

Tom

 

[MalteGuenther]

Had a '61 for 10 years, back in the 70's, bought an '89 convertible last Nov. Spent the winter replacing things, because it's 37 years old and a pathetic Carfax. It is a good example of a fairly well taken care of car w/decent original paint and no apparent accidents. Am used to old school, carburetor/air/ignition, this TP! has me scratching my 75 year old head but I am learning. I drove it over an hour home after purchase, then it went directly in the garage, over the last month I have replaced the injectors w/Bosch111's, replaced the fuel pump, new filter and new diaphragm in the fpr and I am only getting 30# of fuel pressure, starts hard and is a dog. This weekend I reinstalled the old fuel pump and fitted a new diaphragm, although the original looked fine. I’m still getting only 30 psi. After priming the lines, the pressure doesn’t bleed off completely like in some videos; it drops about 5 psi after ten minutes. Could this point to the regulator, a restricted filter, low pump voltage or an inaccurate gauge? I love the car, but diagnosing it every weekend is taking the fun out of driving. Lately it’s been easier to unwind with a few quick slots at Tropica casino Still, I’d rather get the car running properly. What should I test next? Thanks in advance.

Welcome aboard, and congrats on the ’89 convertible. The TPI cars can be a bit of a learning curve if you’re coming from carbs, but they’re pretty logical once you chase them one system at a time.

On that fuel pressure, I’d first verify the gauge if you can, then check pressure with the vacuum line off the regulator and plugged. You should see higher pressure with no vacuum than what you’re reporting. Since you’ve already tried two pumps and the regulator diaphragm, I’d be looking hard at voltage/ground to the pump, the rubber hose inside the tank, a restriction in the line/filter area, or even a weak pump relay/oil pressure switch circuit. Also make sure the return line isn’t somehow dumping pressure incorrectly. The slow bleed-down doesn’t sound like the main issue to me — the low running/prime pressure does.