Has anyone used an MSD fuel pump with their TPI setup. If so, what pump did you use, did you use OEM fuel pressure regulator and did you have pressure problems? Thanks

 

Okay, since no replies have been posted here is the answer. An MSD fuel pump supplies 125 psi. This pressure is too much for a stock FPR. If running the MSD pump w/ stock FPR expect to see 60 PSI. If you read through my other posting Fuel Problems you will see the rest of the information.

 

I think you need a boost inline pump after the FPR so the system can flow enough fuel back to the tank. I did that with my setup so the return line would back up.

 

Are we talking about the external or internal MSD pump. If its the external MSD 2225 I have one on my 383. Its actually an airtech pump, MSD just puts their sticker on it. I'm using an aftermkt regulator but I suspect a factory regulator will work.
Its pretty much tailored for TPI.

 

The MSD pump I have is 125psi pump. I'm not sure what the part number is, but the factory FPR will not work as I see it right now. It appears to be locking up my 19# injectors, and I can't get below 60 PSI on the fuel rail. So I'm going to modify the factory FPR. What PSI are you running on your fuel rail?

 

Also, the pump is external.

 

I'm using an aeromotive regulator I think it should handle most any pump but they are pricey....you can check out the pump I have at summit and see if it looks like yours. search MSD 2225.
It is the same pump recommended in the tpi fuel injection swap guide book. The msd pump you have is recommended for fuel injectiion correct?

 

I do have MSD 2225. Today, I pulled the FPR apart and built a spacer to reduce regulator spring preload in order to reduce the fuel pressure at the rails. I put a screw in the top of the regulator to make the regulator adjustable. This was an attempt to see if the pressure was my main problem. I adjusted the FP to approx 37psi at idle. I will say that the injectors did cool way down. I could actually keep my fingers on the injectors after approx 45 minutes of idleing. I also, reset my AFR to ~14:1. The car still died at approx 50min of run time, but I was not watching to see if it leaned out when it died. I'm not sure if it is dropping spark, or fuel, but I think it is dropping fuel. I may have a component on my ECU that is heating up. I will just have to continue to troubleshoot. I do have to say that I'm running a megasquirt ECU and we haven't ran it over about 50 min, that is why I'm thinking either a component is heating up on the mother board, or perhaps my 8 Pin HEI module is heating up. Thanks for your responses, I will take a look at your FPR. I just wish I could find out if someone has ran the 19# injectors at 60 PSI? Let me know if there is any more advice or questions for me. Thanks

 

Well then if you have the 2225 pump then I think something is wrong like a restriction on the return side because that pump is not rated at anywhere near 125 psi. Maybe you've repaired the pressure issue with your regulator mod. Good luck

 

Unless I'm reading something wrong, 125psi is stamped on the pump housing. Everything looks good with the return line. The homebuilt adjustable FPR works well, but I'm still having problems. Do you know if the injectors should get too hot to touch?

 

Humm

I've never noticed that on my pump but then it is the generic version. That must be deadhead pressure. Can't imagine why a pump of that pressure output would be recommended for Tune port. At any rate I suppose that its okay if you can control the pressure. I don't think the injectors should get that hot from operation. I'm sure they would pick up some latent engine heat though. How much I'm not quite sure. I've never really checked mine. Somehow I think 60 psi is too much pressure but that's just me. My running pressure is 39psi (with vacuum to the regulator)

 

Yes 125 PSI is to dead head, and I agree that 60 psi is a lot high. I created an adjustable FPR and I now have my fuel down to around 34 PSI at Idle. The car will run for between 20 and 40 min, then just die. I took resistance checks on the injectors with the engine both hot and cold and every injector measured between 16 and 16.2 Ohms.(Cold) and some injectors measured up to 18 Ohms when hot. Both the cold and hot seem high to me. Any Ideas?

 

I wonder if you have ecm problems? When it dies will it restart? Have you checked to see if you lose injector pulse or spark?

 

I have a logging function on the computer. All monitoring looks good up to the point the car dies. I'm not sure if you are familar with mega squirt, but that is the computer I'm running. I guy I've been talking to has mentioned pump cavitation. Have you ever heard of this?

 

Oh and the car will not restart until it cools down. At least that is how it appears.

Mike

 

Yes I'm familiar with pump cavitation. What I would do if it were me is see if you loose fuel pressure just before it dies. However with pressures as high as you've been seeing I don't think you have a cavitation problem unless you mounted your pump highter than the tank. It is possible however that the fuel pump could be failing. The symptom you describe is typical of pump failure. However it also it typical of distributor module failure, and ecm failure as well. If fuel pressure looks good when it dies and is not restarting see if you are loosing spark or injector pulse. I bet you don't have or the other if pressure is good. Fuel, ignition, mechanical thats still what its all about... I'm not real familar with the ecm you have. Isn't that the DIY ecm?

 

The ECM I have is one that I built. I have the ability to log all of my functions except fuel pressure and actual spark output. Also, I have a cut away dizzy cap so I can see spark. When the car dies it appears that the fuel pressure stays constant. I can turn the ignition on and off approx 4 times to get fuel in the cylinders. The car will start and run for a few seconds prior to dying. This is the first fuel injected car that I've really worked on, and I have learned a ton, but I still have a few uncertainties. It is possible that the pump is failing, but it sound pretty healthy even when the car dies. I do have a clear fuel filter between the pump and the tank. The one thing I've worried about is that when the car runs the fuel filter appears to be less than half full of fuel. This seems strange to me. Also, last night during testing, after the car died, I turned the key off, then back on to get a priming pulse in the cylinders. It sounded like their was air in the fuel rail. Hopefully I will get to work on the car some more tomorrow. I'm going to remove the filter between the pump and the tank and see if anything changes. Keep your idea's rollin'. It is good to have a sounding board. If your interested in hearing about my ECU I can tell you more about it. I'm not too familiar with how and 8PIN HEI module fails. I'm pretty sure that the problem I'm having is still fuel related. One thing I did last night was to measure the resistance of the injectors when they were cold. All of the resistance checks fell between 16 and 16.2 Ohms. This seems a little high. After the car heated up, some of the injectors measure approx 17 Ohms. I'm not sure if this is a big deal or not, I'm just reporting what I did last night. Thanks for your help. I'll keep you posted.

Mike

 

So, I removed my fuel filter out of the loop and put a clear line in it's place. I started the car and I have the same results. The car runs for a while 20-40 min, then leans out and dies. I pulled the coil wire and I get a good blue spark. I did this a couple of minutes after it died. The pressure remained constant on the fuel rail. Also, I checked my fuel lines to see if there was any portion of the line that was hot. I did not find one. I'm beginning to run out of things that would make the fuel a problem. I'm pretty sure I'm not dropping spark. I check the relay on the ECU to see if it was hot. It wasn't. I think I may remove the fuel pump from the back of the car and hook it directly to the fuel rails. Drop two lines in a 5 gl gas can and see if I have the same problems. Honestly I'm not sure what this will accomplish. I may be able to hear the fuel pump better if it is stumbling, but with the pressure maintained on the fuel rails. I can't imagine my pump being bad. When I turn the key on and off I can feel the injectors firing. I'm at the point where either the fuel is flashing to a gas in the rail due to heat (which I can't imagine is happening) or perhaps I have a problem with one of the components on my ECU. If you have any ideas let me know 'cause I'm running out. Thanks for all your help.

Mike

 

So here were the results. My 8 PIN HEI module was heating up and I would drop spark for long enough to kill the car. This is what I did to check everything out. I removed my fuel pump and hooked it up to the fuel rail with a clear supply and return line. I placed the fuel pump pickup and the fuel rail return in a 5 gal gas can. I set everything up so that I could watch it all at once. I hooked the fuel pump directly up to the batt to bypass the ECU. I ran the car until the MAT again heated to 121F. The car died. Everything looked good. Fuel Pressure was stable, return was stable, I could feel the injectors firing. This time when I pulled the coil wire the spark was yellow. So with my cut away dizzy cap I started the car and watched just the spark. It appeared that the spark cutout so I put a timing light on the #1 plug wire and started it up. Sure enough I dropped spark again. I pulled the old 8 pin module off, and the bottom side of the module that is supposed to have grease on it to dissipate heat did not have anything on it, and it about burnt my finger. I put the new module on within about 5 min of the car dieing. The car cranked up and it ran until I shut it down. No leaning out and dieing this time. I spoke with one of my friends (Moby) about the Wideband 02 reading and he came to the conclusion that if we are dropping spark we would get the same reading on the wideband as if we were dropping fuel. Reason being is we would expel a cylinder full of unburnt fuel as well as 02. This would cause the readings to be lean. So, for the moment all appears to be well. I have not driven the car yet as I'm going to mess with the fuel rail a little more before taking her out on the road. Let me know what you guys think. Take care and thanks for helping me out.

 

Hey Glad you got it worked out. I've been away from the computer all weekend working our oval track car..Nice looking street rod!

 

Again thanks for the help, and the streetrod comment. Hope you had good time working on the track.

Mike