Derrick_12341

So, I'm only getting about 20mpg. I've replaced the o2 sensor, set the timing correctly, replaced the spark plugs, checked the fuel pressure (35psi which from my understanding is normal),and had the car checked for gas leaks(was told everything around the gas tank, lines, and injectors were all dry). One thing I've noticed is that when I'm driving with the A/C on especially I get a slight gassy smell, also, when I turn the key to the '' ON " position the fuel pump keeps pumping instead of turning off after a few seconds until I turn the key back off. Another thing is that when I'm driving and come to a stop the idle jumps from normal to around 1300rpm and throws a check engine light(but it doesn't throw a light on the ECU). Any ideas about what at least some of this crap could mean?

acmoc

35 psi is low.
Should be 39-42

Derrick_12341

It was like 40 with the FPR vaccume hose disconnected and like 35 with it connected.

acmoc

Oh, thst's fine then. Look for vacuum leaks.

Derrick_12341

Checked out the wiring to the fuel sending unit and the fuel pump and this is what I found

The wire on the right looks out of place. I traced it back and it connects to a brown wire under the driver side dash near the fuse box. Any idea what that wire is for?

Tyson

well no, that doesnt look normal. are you referring the main relay where that wire leads to?

theres electrical and shop manuals available for download. that should help you and look up info yourself.

its obvious now the previous owner had an issue that isnt fixed properly. fixing these unique situations is difficult, you just have to troubleshoot it yourself.

LankorDie

Looks like his main relay **** the bed and he wired this up to go around the relay.

Replace the main relay, then cut that wire. You might be getting a voltage drop from a smaller gauge wire to your electronic fuel pump. You could also hardwire your fuel pump with a larger gauge wire so you don't have to worry about this in the future.

Derrick_12341

Is there any way to test for a bad relay? What are the symptoms of a bad one?

LankorDie

The fuel pump doesn't arm with the key in the on position.

Derrick_12341

Hmmmm. Well when I got the car this work had already been done obviously so there's no way to check besides undoing the wiring. But what I have noticed is that when you turn the key to the ON position it stays on until you turn it back off again. Could that support the idea that the relay was jumped?

Tyson

yes.

its supposed to prime for 5 seconds or so in the ON position. then turn off.

its clear they jumped it, why? no clear answer other than theres something that was wrong and did not fix correctly.

Derrick_12341

Thanks for the replies guys.

You can't see the other wire it connects to because it's brown but that's where the extra wire goes under the dash(ignore my face lol). I tried to trace the brown wire and it leads to a plug next to the injector resistor box. Is this wire important or is it just power or something?

Tyson

ugh. so its just powered from the fuse box?

you really need to take your car to a shop, maybe a stereo shop can help you since they would have the electrical skills to troubleshoot and figure things out in person for you.

Derrick_12341

Sorry for all the questions. We all gotta start somewhere. Upon further inspection it does seem to be spliced into a white/red wire and that plugs into the fuse box. So yes I'm assuming it's powered by the fuse box.

Tyson

How about you start with downloading the shop manual like I said. It has all the info on how it should be.

Derrick_12341

Okay, I replaced the fuel relay and undid the wiring and the fuel pump primes as it should now. However, I'm still getting terrible gas mileage. I talked to the previous owner and he told me the original map sensor went bad and so he got another off a parts car. Is this something I should look at next? Aside from the gas mileage I don't really have any other issues with how the car runs.

Derrick_12341

This is the plug for the distributor. All the wires seem to be the correct color except for that yellow/green one. I can't seem to find any info about that one. Is that color wire supposed to be there?

DaX

iTrader: (1)

I'd recommend you average your mileage out over the next 2 full gas tanks before you conclude that you are still getting bad mileage. Are you still having the issue with the CEL coming on but no codes being thrown? The car doesn't run rough does it? Have you checked compression? Pull your spark plugs and take a look at them.