Casey Robertson

iTrader: (2)

Hi all! I leave near SLO - CA and we have a large hill on the 101 I drive up daily. A few things with my car recently.

1. While in 5th gear, if I floor it going up the grade I build boost up to the normal 18-20psi max and it holds but the car just feels like it won't go. Almost like hesitations. Did some reading and wanted to get your feedback:

a. Spark plug issue at WOT and 5th gear?
b. MAF sensor cleaning?
c. Cone air filter cleaning?
d. Combination of all?

2. Issue 2 is about 3 times in the last 2 weeks the car has "died in flight" So far it has happened at about a 30mph right-hand offramp, when pull through a left hand intersection and this morning when coming to a stop. I've had an alternator die before and it's not acting like that (accessories acting weird, car missing/lurching). Car fires right back up and drives without issue.

a. Battery cable issue? Car shuts off to protect alternator over-current?
b. Alternator cable issue?
c. Alternator issue?
d. ???

My plan of attack for all of the above so far is:

1. Clean MAF
2. New air filter
3. New spark plugs
4. Test battery (almost brand new but will check regardless)
5. Get alternator tested (haven't done this before)
6. Get new battery cables/alternator cables or terminals

More invasive - alternator testing/replacement

Appreciate your time. Other than above mentioned scenarios, car runs great. Got it 2nd hand so honestly no idea if/when the consumables (spark plugs, filter etc) have been done recently.

Thanks,
Casey

cts4g63

iTrader: (1)

I would be careful about how often you put that much load on your engine in 5th gear.

Casey Robertson

iTrader: (2)

Ok- thanks for the heads up. Just noticed randomly. The car normally cruises A-ok at 70mph up the hill in 5th. No lugging etc. Just noticed recently when trying to get around a slow truck etc

Biggiesacks

check all your grounding points and clean your battery terminals. You shouldn't be going WOT in 5th gear unless you are doing like 120mph or what ever the top of 4th gear is. You where probably getting ignition retard because of engine knock. You would feel miss fires much more dramatically if that was what was happening.

egis

are you on SD and do you have wide band.

Casey Robertson

iTrader: (2)

Sorry - newb here...but assuming SD = speed density and wide band is a kind of sensor.... I'm 99% sure the answer is NO.

Casey Robertson

iTrader: (2)

Some more info. So I can kind of replicate it.... if I'm going about 30mph and press the clutch in and let the revs die down...they will drop to about 500 and MOST of the time go back to idle ~1000rpm but a few times it would just die. Not sputter or miss but just like the RPMs would keep going down. Doesn't seem to happen at parking lots speeds in 1st or 2nd gear etc.

Anyway, what are your thoughts on fuel pump and/or filter too? Also cleaning injectors? Car is totally driveable but this is kind of an annoying. At 84k mileage and relatively unknown provenance I feel like everything I'm thinking about doing is probably normal maintenance type stuff. Appreciate the feedback.

This weekend I will do the air filter, clean the MAF, do the plugs and go from there.

Epyon

iTrader: (1)

I'm not totally sure if the 8/9 evos have a similar issue, but I know during hard left turns on the X, sometimes you can starve the fuel pump due to the tank design so not sure if that would contribute to the on/off ramp issues.

But how is your idling? Sometimes if a Vacuum line pops off or leaks it can cause a rough idle and when dropping out of gear it won't be able to recover the idle speed due to vac leaking. If your idle is nice and smooth you probably don't have any vacuum issues though.

Casey Robertson

iTrader: (2)

Good point on the vacuum lines. So I have a boost gauge...forgive my ignorance but is the vacuum that is indicated on the boost gauge indicative of overall vacuum in the entire system? Is is there a part of the vacuum system that is isolated from the turbo system?

When I bought the car it was only building 12lb boost but that ended up being due to the solenoid boost lines being modded and missing the restrictor pills. Got a new assembly and that was solved.

From reading it sounds like if you have a vacuum leak the idle will usually go UP a bit?

If I had a vacuum leak, should I expect the boost gauge at idle to creep upward in pressure or down? I presume up because it can't hold a vacuum?

Good learning on this site - thanks for the help! I'll check the vacuum lines visually when I do the other work and might construct one of those boost leak testers I've seen (assuming this tests all the vacuum lines I need to check).

Ev0ikon

iTrader: (18)

Sounds like your clutch is slipping.

Casey Robertson

iTrader: (2)

Any recommendations for testing that theory?