I have an aftermarket fuel pump that i just replaced on my car. The car will run for a short period, driving it and it dies, as if it is starving for fuel. I can wait for a minute and it will restart. It only does this under a load, idling no problem. I was wondering if the fuel pump I put on does not have enough volume for the car? Has anyone had this problem? Is the oem fuel pump the only pump I should use?

Now, I am chasing 2 problems, the second is some carb issues. I have determined that the accelerator pump needs to be addressed, I am getting some hesitation on acceleration. So I will fix this as well. Are these two items related or separate problems?

 

Need more information Doc....
What kind of pump do you have? Is it "regulated"? What is the fuel pressure you have it set to? When was the last time you changed the fuel filter? Have you done a volume test at the carb, as per the FSM?
Post answers to these questions and the knowledgeable people on this forum will be able to help.
As far as the accelerator pump....could be related, but answering the above will help pin-point problems....my guess:

1. Clogged fuel filter
2. Carb needs a rebuild and proper "tune"

But these are absolute blind guesses.

 

What kind of psi does this aftermarket fuel pump produce? I know these cars only need like 2 or 3 psi to run and having too much will cause problems. Just a guestimate I would say being aftermarket you may need a regulator along with the fuel pump. Especially if you're still using the Nikki carburetor. If you have upgraded the carburetor then maybe you need a more powerful fuel pump.

 

Thanks for the prompt responses, go easy on me as i am not very mechanical and this is my first attempt at this type of situation.

This car was pulled from a garage, was my parents car after sitting for 15 plus years 9100 miles on it.

I have never done anything like this before so my knowledge is limited, and thanks to many of you on this forum, I have made leaps and bounds getting this car up and running.

Now let me see, I am not sure if it is a regulated fuel pump or not. I purchased it at an auto parts store that was supposed to be the oem replacement. Not sure of the pressure as well, do I need to check this? If so how do I tackle that one?

I did not replace the fuel filter, that just hit me like a ton of bricks! Wow what an item to overlook. I will replace that today.

The carb will be rebuilt again this week just to make sure I did not do anything wrong. I will have my neighbor who is a mechanic assist me this time. I know the accelerator pump is bad or maybe I did something wrong there?

Did I miss anything? Be gentle we are treading on tough ground for me....

 

Welcome. If it's been sitting that long you will probably find varnish and gunk in your fuel tank. Definitely need to drain any old gas. Later models have a drain plug in the bottom of the tank. Replace the Fuel filter at least. With that low mileage you should drop the tank and clean it (or have it professionally cleaned). When you are sure the tank is clean disassemble and clean the carb. What model and year car are we talking about? We love pictures.

79-85 Carb Manual can be downloaded here. 79-80 PDF page 45, 81-82 page 77, 83-85 page 103.
http://foxed.ca/foxed/index.php?page=rx7manual

 

I was and well still currently in around the same position as you and there were many people that have helped me with my car from this site. I have been having a hesitation problem with my car since I got it over a month ago lol. But for sitting for so long I am sure all filters need to be changed, fuel, oil, and air. A clogged fuel filter can cause many problems since you're not getting as much gas as you need. And as far as the fuel pump, if it is like the same one I have that you can purchase at just about any auto store that is universal then it should say on there somewhere how much psi it delivers. Also you have to purchase a fuel pressure regulator if it is aftermarket, or could feed too much gas to the engine. I am not too sure myself on how to install the regulator since mine already had it when I got the car but if you are in need of one I am sure there are instructions or people on here who can help you out.

As far as the hesitation, I am still trying to figure mine out myself lol. There is a thread I created on here recently that has many people walking me through different processes to check and all the problems I have come across so far while doing it. If you want you can check that out to maybe give you a few ideas you can test.

But I definitely know how you feel about the mechanical knowledge part lol. I pretty much know the basics and how to fix what has already happened to previous cars I have had. Which this is my first rx7 and my first carbureted system. So it is an all new adventure for me, but there are many people here who will help and also lots of info in this whole forum. I am to the point to now I have this website open in a tab before I get on facebook! Just waiting for a response or a new thread to read up on to learn something new.

 

he said he got an OEM replacement pump. so ill dismiss that for now. like others have said. drop the tank and clean it. get it lined. replace the fuel filter. if it still does it i would rebuild the carb. also, you may want to look into replacing all the soft fuel lines. as they age they deteriorate and clog up your filter, carb, etc. depending on how old they are. i would definitely change them before putting the rebuilt carb in, if they are fairly old. fuel line is cheap and often overlooked.

 

Follow this link to my original post of this car:https://www.rx7club.com/new-member-rx-7-technical-256/1982-rx7-what-do-i-do-950046/

 

I did replace the tank, the fuel lines and such already.

Now here it gets weird. i checked the fuel filter, which I did change out last week. The car started running fine, no problems except a small miss. i pulled plugs and cleaned them and it cleared up. I drove it for about 5 miles and shut it off and cleaned it up, first bath in 15 years. I tried to start it and she would not stay running. Then after 4-5 trys it started and ran fine again. I did notice that the idle rpms came up to 1200 at one point before going back down to 800. Not sure about that yet.

My plan is to get another rebuild kit and go thru the carb again. I will also replace the plug wires, cap and rotor next. I also put new tires on it today. I took my son for a short ride around town. I need to get new rotors and brakes for the front. I also have a thumping sound coming from the passenger side of the car when I hit any bump. I am thinking maybe exhaust??????

Other than that the car runs pretty damn smooth, I have been really impressed with it so far. As long as I keep making forward progress, I am happy.

 

I had a similar problem he other day and my primary jets were clogged. i wouldnt **** around with the stock carb... I know a lot of people who love them but this end up happening to you lol
And i would say prolly the exhaust is hitting..... any sloppy front end handling of any sort? and yes...... we do love pics!

 

lol, nothing wrong with a stock carb. They work great when they work, and I think they are less problematic than any of the others.

When you rebuilt the carb the first time, did you remove and clean the fuel jets? These are located in the wall of the float bowl, down at the bottom. You access them by removing the four brass plugs. If you didn't, then this would be something to check.

Also, there are some small parts associated with the Accelerator pump which often get misplaced during rebuilds. I think there's a couple of little ball bearings, and a brass weight.

One thing you could check for me, which should help narrow this down:

Drive it until it dies, shut off the key, then check the fuel level in the float bowls. This will tell us if this is being caused by starvation.

Good to see you continuing to make progress!




.

 

hanks for the responses. i saw your post on the other thread i have as well.

This car continues to drive me crazy...LOL it ran great today with a few glitches. I just need to rebuild the carb again and see if I did something wrong or perhaps is clogged. It isn't dying now like it was...weird. Sometime though it is hard to start, go figure. But....I put 25 miles on it today just driving around town. that darn noise that I think is the exhaust is driving me nuts. I have to put it on the lift and see what it is. Seems like it is improving the more I drive it. I am still not comfortable with taking it very far yet.

 

well if it sat for a while they seem to really come to life the more and more you gingerly break her back into driving......... then eventually it will do what mine does...... if you neglect her for more than a week of not driving she gets a little angry with you and acts like she doesn't wanna start for ya. lol these girls have such attitudes some times.

 

If you are able to drive around with it, and the carb issues seem inconsistent, then personally I would just dump a can of Seafoam into the gas tank and continue to drive it. A lot of time, all they need is some excersize.

 

+1 on the Seafoam.
That stuff works wonders

 

I added some seafoam to it the other day thinking the same thing. I am continuing to drive he on short little trips around town and making loops around the neighborhood daily. It seems to be getting a little better.

 

So when you swapped the tank, did you clean and seal the NEW tank first? Maybe otherwise you are inheriting someone else's problems. For me the bad-tank issue only showed when the tank was below 1/2 full. Ran great on a full tank. Something is plugging your fuel system (like you don't know that).
re-checking your fuel filter might confirm more gunk coming from tank....

Stu Aull
80GS
Alaska

 

I did have the new tank cleaned and recoated, however I think I will keep an eye on the half tank situation. I have been running on a full tank. If this happens at a half tank it will be time to remove again. Thanks for the information.