Introduction and a question on poor starting.

[renaissanceman]

Hello all! Some of you may recognize me as ColonelHogan44 over at Suzuki-Forums. I thought I'd introduce myself.

My 1996 tracker (USA, 2 door, 4x4, auto, 16v) has had a persistent poor starting condition. It will start dead cold ok, with a little stumbling, then rev to about 1000-1200 and run ok. fully hot, it always starts, with just a little stumble. When it's warm, it will crank and crank and then catch after 2-3 seconds, often stalling out. On the second attempt, it stays running generally. With a little bit of throttle, it starts very easily. When I began, the long term fuel trim was 1.8, showing a little tiny vacuum leak.

Once it's running, it runs BEAUTIFULLY, and I get 28-30 MPG with my automatic tranny. Great power. The ECU can hold an 800 rpm idle regardless of loads (headlights, in and out of gear) and bumps it up to 1000 with A/C

So far I have:

1.) Checked timing, it is correct at 5* BTDC. Plugs and wires are new, as is the cap/rotor. Doesn't seem to be an ignition problem.
2.) Checked plugs, gapped to 0.028. No carbon, they look perfect.
3.) Checked EGR, It was loose, but very clean, functional and not clogged. Cracked gasket. Cleaned(just because I'm OCD and it was off, so why not??), replaced with a new gasket. Long term fuel trim is now 0.0.
4.) cleaned the MAF sensor with CRC MAF cleaner. No change.
5.) pinched all vacuum hoses and sprayed carb cleaner on the connections. Nothing.
6.) Replaced the PCV valve. No change.

I'm starting to suspect the wax pellet based IAC valve is not opening. What's the best way to check this? Any other ideas on what to check next?

[fixkick]

Howdy Partner !
hot start, late start. (does 10% throttle help ,yes or 100% then?) might be flooding, tiny be on 1 cylinder for injector leak.
The IAC thermal is closed hot, but not ISC, (not sticking)
Remove PFreg Vac hose, is it leaking fuel there? this love to fail (this old) and acts like injector leaks.
does test fuel help or make it worse? (my guess , worse)

engine wants air, so must be starved for air or , injectors leaks. or PFreg.

id run a bottle Techron in the tank on the hope it cleans that injector, if be it.

does key on 3 time help before cranking?

some ideas, wish you well and fix fix.

PS id test the fpreg big time, run it true the vacuum chart.

my crude chart

[renaissanceman]

Is the IAC integrated with the ISC? I'll probably pull that off tonight and have a look.

10% throttle helps it start readily, whereas at 100% it will not start (just cranks and cranks -- it's programmed that way, yes?). Fuel pressure seems to come up very fast -- when it's cold it will fire immediately without waiting for the pump to prime at all.


Plugs all look balanced, so I don't think it's an injector issue:
#1

#2

#3

#4

[fixkick]

plugs look perfect
the cold idle air, iAC thermal is under the Throttle body
the iSc has 3 hoses, 1 air and 2 water. and is electric, idle speed controller mounted to left side if plenum forward of TBody.

when you stop and engine it might leak down, to the cylinders. (the pump like down test finds that. 30seconds, not drop below 25psi? IIRC
the hot starts are worry some
it can be too much fuel, and not start, the burn off and plugs look great.
id check pump leak down, of good. then FPREG leakage. at vac, nipple. it must not leak.
and last isc, actions...

the hot start, has just 2 air sources, ISC and bleed.
so if the ISC is stuck closes, it will have hard starts, unless 5% throttle added. hot.
is the idle switch closed? if not, it may not open ISC correctly

usually old iSC leak air, but some can stick, the PCV cloud filth loves to migrated there.

[renaissanceman]

The idle switch appears to be closed, as the ISC does bump up the idle to 1000 when the A/C is switched on. Any idea why there is coolant going to a purely electronic valve??

Hot starts are not typically a problem (with full 180* coolant temp), but really the warm starts with coolant temp from 100-150*. Here are some videos I made to show:

Cold Start:
https://www.youtube.com/watch?v=49lxLQAknaM

Warmer Start:
https://www.youtube.com/watch?v=N9Jn0pB_mYI

Warmest Start:
https://www.youtube.com/watch?v=eKZsidZpqGY

I never got a truely hot start video made...short trips that day. Next time I have it out on the open road I'll make one.

I'll pull the ISC off and give it a really good cleaning and report back.

[barnbiketom]

mine was similar.. the FUEL PRESSURE REGULATOR vac line showed fuel in it.. bad FPR

[renaissanceman]

mine was similar.. the FUEL PRESSURE REGULATOR vac line showed fuel in it.. bad FPR

Ha, I pulled the vac line, and it GUSHED fuel. Guess I found the cause?

Any recommendations on brand? I'll probably grab the BECK/ARNLEY Part # 1580560 from Rockauto if not.

[gorkyb]

That's the exact part I bought last year for mine and it worked fine on my 96.

[fixkick]

The idle switch appears to be closed, as the ISC does bump up the idle to 1000 when the A/C is switched on. The ISC is ok, then,

Any idea why there is coolant going to a purely electronic valve?? sure, it was added in 1991 to the 8v to heat the whole,TB, and they deleted the base heater, PTC , as a result, and on 16v it heats up the plenum , i presume this helps. but is near same part as 8v. so....
the 16v ISC only has a tube twisted, funny.

Hot starts are not typically a problem (with full 180* coolant temp), but really the warm starts with coolant temp from 100-150*. Here are some videos I made to show:

Cold Start:
https://www.youtube.com/watch?v=49lxLQAknaM

Warmer Start:
https://www.youtube.com/watch?v=N9Jn0pB_mYI

Warmest Start: very slow start !
https://www.youtube.com/watch?v=eKZsidZpqGY

I never got a truly hot start video made...short trips that day. Next time I have it out on the open road I'll make one.

I'll pull the ISC off and give it a really good cleaning and report back.

I suspect that extra air is needed (over normal) because there is excess fuel there, to start; Is the FPreg leaking fuel? (at vacuum nipple?)
why not try test fuel?
or make a small vacuum leak, forcing lean.
if engine is good, and spark good it's fueling (egr not leaking)
so add fuel or add air, as a test see if that 3seconds drop stop 1.

one or the other helps prove the case.

does ECT read right? 300ohms hot? cold start fuel is calculated off this too, and most match conditions,

[renaissanceman]

ECTS reads correctly across all ranges, per my scan tool.

FPR is leaking fuel into the vacuum line like a stuck pig. I have a new one on order from Amazon. Should be here Friday.