98 v70xc OBD2 No Power/ Rough engine idle

Bdates · Post by **Bdates** » Sat Jan 19, 2019 6:53 pm

OK...

So I can't properly diagnose my random rough engine bogging because my OBD2 port seems to be powerless. My Scantool isn't reading, or even turning on. Its not the tool because it used to work on my old 98's in the past and olaso used to work with this car. It still works on my wife's 08 Escape. I couldn't find anything info about a fuse, except that it may be connected to the cigarette lighter. Both cigarette lighters have power (only if I turn my charger at the perfect angle).

As for the random rough idle... I have cleaned the MAF sensor with spray, I have cleaned the AIC valve with throttle body cleaner, I changed spark plugs, I checked fuel pressure (seems to be fine, needle was vibrating between 30-40psi, however it was a harbor freight kit) so that means it can't be the fuel pump or fuel filter. I changed the Air Filter. I didn't see any hoses disconnected anywhere. I took the fuel rain off and check out the fuel injectors, they seem fine, no noticeable clogging.

I'm thinking maybe I will have to replace the injectors, but trying not to throw money at it until something works.

I want to check the code so badly for a pointers! So frustrating. Did I mention I have 4 12-hour trips coming up in a month?

Post by **abscate** » Sun Jan 20, 2019 1:29 am

Cheap things to try

Open up the distributor cap and rotor and let's see pictures of inside

Swap coil for known to be good

Jumper the fuel pump relay with a wire ( your fuel pressurediagnostic does lead away from this, agreed, well done)

Is your battery voltage strong, 12.4 volts or better?

Bdates · Post by **Bdates** » Sun Jan 20, 2019 9:25 am

I already jumped the fuel pump relay, and tried an old one I had sitting around.
Haven't tried the distributor cap and rotor yet...
Battery is good, I think 12.2 volts but I will check again.

Update from just driving it into town for about 20 mins...
It definitely seems to be worse when cold. The car seems to die when in gear easier when a load is put on it without the accelerator. For instance, when simply shifting into reverse or when coming to a stop while in drive. When accelerating and cold out, I'd say about 60-70 percent of the time the car has minimal power instantly, then jumps up as if I only then pressed down on the accelerator. The car will jump and die in power with minimal accelerator pressure, but if I stomp it it will jump once or twice, then work as it should till about 4k rpm.

Post by **abscate** » Sun Jan 20, 2019 10:21 am

I missed this earlier.

, I checked fuel pressure (seems to be fine, needle was vibrating between 30-40psi, however it was a harbor freight kit) so that means it can't be the fuel pump or fuel filter

Vibrating fuel pressure isn't good. Relay , wiring, pump and fuel pressurecregulator (FPR) need evaluation

Bdates · Post by **Bdates** » Mon Jan 21, 2019 4:24 pm

For a 98 v70 xc the fuel pressure regulator is behind the passenger front wheel?

Bdates · Post by **Bdates** » Mon Jan 21, 2019 4:43 pm

Here are the old cap and rotor and the newer but used cap and rotor...

abscate wrote: ↑Sun Jan 20, 2019 1:29 am Open up the distributor cap and rotor and let's see pictures of inside

Here are the old cap and rotor pics and the newer but used one i installed with newer used wires.

Bdates · Post by **Bdates** » Mon Jan 21, 2019 4:45 pm

First two pics are the newer ones I installed.

WhatAmIDoing · Post by **WhatAmIDoing** » Mon Jan 21, 2019 7:01 pm

Other than being dirty, they look operable. Wouldn't hurt to clean them up a little.