No power under boost...and some popping


Jun 26, 2007
So this just started today. Car ran great before, all of a sudden no power at all under boost and popping through the intake. The boost guage goes up as usual and at 10 lbs it feels like 0 lbs with a whole lot of hesitation. It will backfire through the intake if I push it further. Runs great when not under boost and no lights on. I know you guys will ask for scantool readings but...I dont have them. New owner and have not had a chance to get all the stuff. But like I said, car feels exactly the same if I dont get into the boost...runs great, once I get into it, thats when the bad things happen. Thanks for the help.
I sent you a PM, but sounds most like either ignition module or coilpak. Once you demand more power, going into boost, the module/coilpak can't deliver, hence popping and missing.
If it runs great at idle and will rev up fine in park, once you put the car under a load and it starts popping thru the intake its the coil pack and module.

Red Regal T is correct :smile:

Yes, it idles good and I just went into the garage and gave it the rev test. Revs ok at all rpm levels with the car in park. Will rev to 3000-4000 if I push it that far. Does not build much boost at all but there is no backfire. Little smoke out the pipes but I think thats my TT chip running just a bit fat.
Consider the MAF sensor? I have one that idles great, but once you apply "go" it drops out and starts sputtering/popping.
I should have explained a little more about a bad coilpack and ignition module.

The car can idle and rev in park just fine, but once you drive the car and put it under a load the car can stumble real bad and make the car pop, spit and stumble.

If you have someone local that has that part, try swapping it out to see if that is the issue.

Issue is the fuel pump. Tried good coil pack and MAF with same results. My car has an external fuel pump that I never use so we decided to hook it up and see what happens. As soon as the pump was on, car ran fine. Drove it like that for a bit, and here is the real strange thing........this morning I drove the car with the external pump turned off, and car felt fine. Weird.
Check all your intercooler hoses. I had this same thing happen and it ended up being a split in the hose from the turbo to the intercooler. It had a split in the bottom where it couldn't be seen and every time it went into boost it forced the split open and started popping.
Sounds like a collapsing sock to me. If it ran fine the day of, before the switch, then the issue may not be the fuel pump. There are relays on both inner fenders under the hood. the ones on the passenger side- Pop the connectors off and look to see if theres a bunch of dried out, hardened dielectric grease covering the sockets, and on the pins of the actual relays. One of the those relays drives the fuel pump. Without a means to collect data, you'll be running around with no success. You need a scan tool. Get a scanmaster. Best money you'll ever spend. Without it, owning a car like this is pointless. My uncle, Chris Werner, was the original owner of billy chaffin's N/A V6 cop car regal. The car was originally, originally owned by duttweiler, and Chris bought it off of him. Duttweiler built the whole car as it still sits today. Chris started off with an 86 t-type. That was his daily driver. A few years later is when he bought Duttweilers red regal and they did the SS/CX buildup that set all those records...I remember going for a ride in the 86 the day after he bought it. I grew up with datsun 210's, so I had never felt power before. Even as a stock 14 second car, I was amazed. Anyway, Duttweiler eventually did everything to that car as well. Chris had poly bushings installed in the front end and 3.90 gears before he even took delivery of the car. Back then, no one knew yet that gears didnt help on these cars. This was very early on so they didnt really know what they were doing. He eventually had a set of the very first GN1's off of it..prototypes I think. A matching intake, turbo was a little bigger..barely...probably a t-3. (dont know what it was), custom headers, cam, 3' exhaust no cat, 4000 stall converter lol! The whole motor was balanced and blueprinted...old school stuff. When that thing spooled up and the TC finally grabbed, it felt ungodly. His best time was like a 12.09 with slicks, 20psi and race gas. That alone felt so incredible to a 15 year old kid who grew up with economy cars. That car is what wrecked my life forever. :D Problem was, he kept frying engines. One piston after another after another after another, kept getting holes burnt through them. He did drive that car really hard. He did regular banzai runs at 150+mph and would stay there for minutes at a time. I didnt really know much about fuel injection or "modern" technology at the time, so I knew nothing about MAF's and bigger injectors and fuel pumps and what not. I saw Chris a couple years back after not seeing him in 10 years. I asked him questions about the car that now I could understand. I said "it had bigger injectors, right?" He says "nope...stock" "bigger fuel pump?".."nope...stock". Stock MAF? "Yup". Chip? "yeah a hypertech off the shelf chip". "better intercooler?" Not really. Stock but modified. That car is what spawned the duttweiler IC neck.
Back then, he had no scan tools or custom chips or anything. Duttweiler himself was still learning about these things. He had no way to see knock retard or A/F or anything. It was amazing that he was able to drive around with that kind of power back then on 92 octane gas and no scan tools or anything. He was running mid 12's at 16psi. He tried nitrous once after the 12.09. He lifted the wheels, then 1/4 of the way down the track it blew a head gasket. They actually didnt know it was from a lack of fuel. they figured it was just too much cylinder pressure and it let go. A scan tool would have changed everything. Its 20 years later and now we have the ability to save the engines long before anything goes wrong. Get a scan tool. It should be as necessary as changing the oil. You need it for your engine to survive. Its not 1986 anymore:eek: