Good Sam Club Open Roads Forum: Search
Open Roads Forum Already a member? Login here.   If not, Register Today!  |  Help

Newest  |  Active  |  Popular  |  RVing FAQ Forum Rules  |  Forum Posting Help and Support  |  Contact  



Open Roads Forum  >  Search the Forums

 > Your search for posts made by 'vacuumbed' found 12 matches.

Sort by:    Search within results:
  Subject Author Date Posted Forum
RE: 1991 P30 454 intermittent surging, power loss

I really appreciate everyone’s help, but for right now my time has run out for troubleshooting this. I have to leave with it on a trip tonight for a festival, and I will be gone until after Labor Day. I will have to resume troubleshooting when I get back in September. When I get back, I will learn how to pull the codes and post them here. Thank you again for everyone that has contributed, and try to help me.
vacuumbed 08/24/22 09:37am Class A Motorhomes
RE: 1991 P30 454 intermittent surging, power loss

You say it bogs down when accelerating at low speeds, what does it do at high speeds? It this problem only at low speed? when engine is hot? Does it run better when engine is cool? Does it run fine once you get above a certain speed? Have you checked the timing yet? Base timing should be 4 degrees BTDC, 454's run better when timing is advanced to 9 degrees. It almost sounds like you're not getting advance when you accelerate if your problem is ignition or you're not getting fuel flow from the fuel pump if it is a fuel issue. Your pressure could be fine but if you don't have the correct flow rate, it can cause hesitation. There is a spec for this, x number of units per min. If you pump is original think about how many gals it had to pump at 8 mpg verses your car at 30 mpg over 58k miles. There seems to be no rhyme or reason, sometimes it will accelerate perfectly fine and it doesn’t matter if the engine is hot or cold. The problem is just at low speed, and accelerating from a full stop. Once it gets up to high speed, it doesn’t seem to have a problem going down the road.
vacuumbed 08/24/22 09:34am Class A Motorhomes
RE: 1991 P30 454 intermittent surging, power loss

**New update** I rebuilt the TBI throttle body. I really did not find anything wrong with it, but it's done. Bought a new A1 Cardone distributor. It has the same reluctor design as the original GM. It also has two holes with screens on the base plate, presumably to address the moisture issue inside the distributor. I like this updated design. The new distributor was easy to install with no problem. Spark plugs were Autolites, I replaced them with AC/Delco. Spark plug wires were the original AC/Delco. One of them had a large split in it, near cylinder #1. I installed a new set of AC/Delco wires. **Test drove, no change. Problem is still present.** It bogs down when accelerating at low speeds.** I tried disconnecting the MAP sensor and guess what, It runs much better!! Ordered a new AC/Delco MAP sensor, installed it and test drove. Ran good, but only for 15 minutes and the problem is right back. Disconnected the new MAP sensor, and it runs much better! The hesitation is still there a little bit, but it runs significantly better with the MAP disconnected. Every time I disconnect the MAP, I plug the vacuum port. FYI I still haven't looked in to pulling codes on this, but the CEL (Service Engine Soon) light comes on immediatley when the MAP is disconnected and turns off when it is reconnected. I am starting to wonder if the PCM is bad. I should have bought a FORD! This thing is very frustrating.
vacuumbed 08/23/22 03:28pm Class A Motorhomes
RE: 1991 P30 454 intermittent surging, power loss

**Update** I removed the fuel pressure regulator. Nothing was visually wrong with it. I am going to proceed with a TBI rebuild kit from NAPA. I decided to remove the distributor cap. Cap and rotor have seen better days. The reluctor (Star wheel) is cracked in 3 places! And it is rusty. I think the rust is common in these units. I may look at replacing the entire distributor.
vacuumbed 08/20/22 02:55am Class A Motorhomes
RE: 1991 P30 454 intermittent surging, power loss

Did you change the fuel filter? Yes, I installed a new Wix fuel filter.
vacuumbed 08/20/22 02:51am Class A Motorhomes
RE: 1991 P30 454 intermittent surging, power loss

Next, I am going to rebuild the TBI and replace the fuel pressure regulator diaphram. I will report back. Thank you everyone.
vacuumbed 08/19/22 09:45pm Class A Motorhomes
RE: 1991 P30 454 intermittent surging, power loss

I just took it for a test drive, the new TPS did not resolve the intermittent hesitation issue.
vacuumbed 08/19/22 07:39pm Class A Motorhomes
RE: 1991 P30 454 intermittent surging, power loss

Since it was acting like a carburetated engine with a bad accelerator pump, I decided to replace the TPS with a new AC/Delco. I haven't driven it yet, but I will soon and report back.
vacuumbed 08/19/22 02:09am Class A Motorhomes
RE: 1991 P30 454 intermittent surging, power loss

Another item is the Idle air control valve. AIC The valve doesn't go bad, but the small passages get clogged. It is on the side of the throttle body, mounted with two very small screws that break easily. Can the AIC affect drivability above idle?
vacuumbed 08/17/22 12:02pm Class A Motorhomes
RE: 1991 P30 454 intermittent surging, power loss

Is the check engine light on, if so I'd borrow a code reader and start there. If not, new plugs and wires would be on my list first. No CEL, it does come on when the engine is started and then it turns off. So it is operational. I saw the plug wires last night, they appeared to look fine. I will look at them again today, and see if there's any warning signs of wear or arcing.
vacuumbed 08/17/22 10:04am Class A Motorhomes
RE: 1991 P30 454 intermittent surging, power loss

Good morning everyone, the fuel filter is a great idea. I am going to do that first today, and I will report back with the results. Thank you for your replies. :)
vacuumbed 08/17/22 10:00am Class A Motorhomes
1991 P30 454 intermittent surging, power loss

Hi everyone, I just bought this 91 Damon Challenger P30 454 TBI and it has this intermittent issue at slower speeds. It doesn't do it all the time. It idles fine, has trouble accelerating, power loss, massive engine speed surging while driving, and an occasional backfire through the intake. If I shut the engine down for 10 minutes, it may run perfectly fine. Air filter looks new, and both injectors are spraying. Strange issue, I am stumped. Please help.
vacuumbed 08/17/22 03:27am Class A Motorhomes
Sort by:    Search within results:


New posts No new posts
Closed, new posts Closed, no new posts
Moved, new posts Moved, no new posts

Adjust text size:




© 2023 CWI, Inc. © 2023 Good Sam Enterprises, LLC. All Rights Reserved.