45.00 Brand New Fuel Pump SAI Equipped D2

 

It lives! Rowdy Roddy Piper would be proud (you know, from the movie "They Live", you've had to have seen it).

Thanks for all the advice from everyone on this thread.

Unfortunately, I am not still not sure what the problem actually was/is.

First, for yucks, I decided to try and start it without the fuel cap off in the event I had some sort of vacuum issue. It wouldn't run at all.

Then I put the fuel cap back on and I got the same behavior as I had been seeing: engine would start, run up to 4,000rpm for a few seconds, then drop to 200-300rpm, where it would struggle for several more seconds before it died.

Counterintuitive result: I would have expected it to run better with the cap off if I had a vacuum somewhere in the fuel system.

I then went on to swap out the IAC valve for a known good used one I had lying around.

Same behavior initially -- engine would start, run up to 4,000rpm for a few seconds, then drop to 200-300rpm -- but this time in spite of the stumbling it just "felt" like it wanted to keep running, so after nursing it along with the accelerator pedal for 30-60 seconds, I finally got it to stabilize first at little higher-than-normal 1,000rpm idle before eventually dropping to 700-800rpm and staying there.

I then drove it around the block, parked it in the opposite direction (so neighbors would also know it moved and so was no longer street art), and then started it again and again at 15min intervals.

Given I still had to nurse it initially to get it to run, I am wondering if I have some still unresolved issue and am just running on borrow time (again). Given my paranoia, when the wife gets home, I will take it for a prolonged drive with her as my sag wagon to see if keeping it running is at all sustainable.

The only other thing I noticed that seemed a little "off", was that when I removed the fuel pressure gauge (it was running at 48-49psi, a bit under the 51psi spec) the gas that came out of the gauge hose after I got it off of the fuel rail schraeder and drained it appeared golden-ish in color rather than clear. FYI, right before it died in October, I had filled it ($2.30 gas at the time!), so I know it has fresh gas. Is it possible that I had previously gotten some bad gas and that could be the issue all along (that and/or maybe the filter on the pump is clogged)?

As I have already done some pre-emptive maintenance -- new CPS, new coil packs, new plugs -- on stuff with nearly 200K miles on it (not the plugs, they only have 40-50K miles on them), I am wondering if I should go long and replace the fuel pump as well? Thoughts on this, especially as I have a full tank that may be contaminated and that I really don't want to drop if I don't have to in order to clean it out (unless someone knows how to drain tank from fuel pump hole without using an electric motor based pump -- I hate explosions).

Also, it is throwing 2 codes: P0102 (MAF circuit low -- don't know why I am getting this as I just put a new Bosch sensor in and replaced the filter at the same time) and a P1884 (came up unknown on my ODBII reader, will need to look this up).

 

You have a bad maf in addition to a bad IAC valve. Unplug it and see if it runs fine.

 

The MAF is a brand new Bosch. Could it really be bad out-of-the-box? Unfortunately, I don't think I have a spare to swap in.

Also, after doing my every 15 min starting it test, I just went out and tried starting it after letting it sit about 2 hours.

It was difficult to start again, misfiring and backfiring and lots of gas pedal feathering and nursing until it got stable. Interestingly, still only the P0102 and P1884 codes, i.e., no misfire codes.

Certainly "feels" like a fuel delivery issue, even though the pressure is nominal (47-48psi). Could you have adequate pressure without adequate fluid volume?

And I unplugged the MAF. With MAF unplugged there is a barely perceptible lag when revving from idle, which is not there when revving with the MAF plugged in. But this was with the engine primed and otherwise "behaving". I'll let it sit for a couple of hours and then test it with the MAF plugged and unplugged again.

And if I didn't mention it, this whole thing might have started about the time the SAI pump quit running (SAI air pump is good, I tested it with 12V and it runs, trying to figure out which relay controls it so I can test that as well).

 

Not the relay, it is the MAF I guarantee it. The 1884 is related to the air temp sensor in the MAF. No need to wait. Just unplug it and start it now. It might be a bit sluggish and idle a little weird but it should eventually idle and run fine once it realizes there is no MAF signal.

 

Given that I had bad luck with my recent MAF purchase (not sure I can return it now, it's been at least 45 days), can you recommend one I should buy (vendor/make)? Thanks.

 

Amazon, send it back right away if it does not work.

 

OK, for purposes of just plugging in another new MAF, what do you think of this one (not another Bosch, but it's the only one with on Amazon with Prime free return)?


If it turns out that the MAF is not the issue, I want the easiest return (ergo Prime).

Also, the fuel pump someone earlier suggested to me came in so I am going to install that in the next day or so.

Regarding the D2, I've started it daily, both with the new Bosch MAF unplugged and plugged in, and it continues to be a bitch to get going -- same revs to 3-4,000rpm, then drops below 200-300 and burps/backfires at what sound like the exhaust manifold (as it is muffled compared to a normal tailpipe backfire) unless the accelerated is feathered along until the idle stabilizes, first at about 1,000rpm, then down to 600-700. But eventually it does get going every time (something it simply refused to do for 4+ weeks prior). And I haven't driven it more than around the block. And same two codes: P0102 and P1884.

Also, on one of the recent daily starts (yesterday or the day before), I actually heard the SAI pump kick on for a few seconds before stopping. Engine was cold, it hasn't done that (run the SAI pump, even momentarily) since.

Gotta get this D2 running before my daughter comes in on the 20th, I don't want to have to rent a car for her: wife won't let our daughter drive her car and all other available running cars I have -- longhood 911, 924S, Boxster(2), RX7 and X1/9 -- are all manuals, which only my son can drive.

 

BTW, given the non-running SAI pump (except for that one short burst one time a couple of days ago) and that muffled backfiring with every labored start, what does anyone think about the other issue that's been floated: clogged cat converters?

We did run it for 9 months with the MAF sensor error before buying the new (bad out-of-box?) Bosch MAF and for several thousand miles, as my brother borrowed it in August to go to Louisiana after Hurricane Ida to do his contracting work for FEMA (rather than his 2WD pickup -- D2 a good vehicle to take to a declared disaster area).

Could running with a bad MAF for so long (5,000ish miles) result in clogged cats?

 

Clogged cat seems unlikely, if it was an issue you would likely see more of an issue under load at high rpm than at idle.