any idea what this engine problem is?

[prabjohns]

Yesterday I drove up to Newcomb's Ranch on the 2.
Car ran fine until I stopped for gas. It took several tries to re start the engine, (I have a hot start issue but that's another thing). The final time I turned the key I had not waited for the engine to completely stop turning from the previous crank but it started. I don't know if that's relevant but from then on the engine ran rough with the occasional "FPSST!" very short high pitched hiss or suck that could almost be mistaken for a very small rock hitting the aluminium floor. A sort of cross between a tap and a hiss. I think coming from the intake side of the car on the right.
I drove the car today and it's the same, maybe worse. Could it be running on three cylinders? Could I have blown a gasket? Or screwed up an injector?

Would love some suggestions of things to try so I can work out what it is.
As you can probably tell, I'm a fairly inexperienced mechanic!

All input gratefully received,
best,
Paul

[Mondo]

I'm no mechanic either but it sounds like a gasket leak of some type... I'd check around intake & exhaust.

[GWise]

That hiss that you hear is actually lean spit back. Those of us with webers know this sound all too well.

Does this happen under any condition? Just Idle, just accelerating, under load only?

Mondo - It could very well be a vacuum leak, but I would suspect not exhaust.

[magnusfeuer]

I doubt that you ruined anything unless you flooded the engine and got a hydraulic lock. Generally there is too little energy in the small amount of fuel that goes into the engine during crank to damage it (unless you blow out your muffler/cat when it backfires).

In addition to answering Gwise's questions, can you explain the other hot start issue you have?

/Magnus F.

[prabjohns]

>can you explain the other hot start issue you have
Hot start problem:
I think it's the starter, not sure if I have a gear reduction starter or not.
Cold, the car starts fine, when it's hot it acts like the battery is very low and has a hard time turning over. Once it's cold it turns over fine again.
I tried putting a blanket type heat shield round the starter but it didn't make much difference.

>Does this happen under any condition? Just Idle, just accelerating, under load only?

The occasional PSST! happens about once every 10 to 20 seconds. It happens at idle and low RPMs driving. It may be happening at higher RPMs but as the engine gets louder at higher RPMs it's hard to tell.

[soareyes]

Paul, the hot start issue seems to be pretty common with the stock Birkin starter. Mine had the same problem and I'm pretty sure Gert's did too. The Gustafson gear reduction starter was the solution:

http://www.gustafsonmachine.com/

The Birkin starter isn't listed on his web site but give him a call and see if he has one in stock.

Stan

[Doug Liedblad]

Is the starter under the headers? Mine is, and with the non gear reduction starter it would do the same thing. Heat shields really didn't help. A relatively small increase in the resistance (like when hot) of the starter can cause large current draw changes according to Wagner Alternator.

The gear reduction starter solved the problem.

I don't recall if Gert has a gear reduction starter or not. If he does he might be able to tell you what to get.

Gustasfason starter is the guy to get it from. He may only sell thru distributors.

[soareyes]

Woody use to sell them but I got mine directly from Gustafson. I think he makes them up in batches for the Birkin depending on demand and I was lucky last year when I ordered and he had a few in stock. It was a direct bolt-in replacement.

Stan

[slomove]

Yes, got mine from Gustafson direct, too. Solved all the embarrassing hot start problems (like needing other folks to push start me at the gas station).

But I think we left Paul's original problem with the hissing/rough running.

No idea what that could be. But since it appeared suddenly I suspect something got lose or lost?

Paul, if you can still make it to my home I can have at least a look over the weekend.

Gert

[prabjohns]

Gert, that's very kind,
I could pop over at your convenience this weekend, let me know what suits you, I'll fit in with that
best,
Pual

[slomove]

Hello Paul,
would Sunday morning (around 10:00 am) work for you? Otherwise the weekend is pretty much booked.

[magnusfeuer]

Hmm. About the PFFFT sound. I wonder if the crank sensor, measuring the position of the crank, is acting up. If it sends signals at the wrong time, it could cause the ECU to fire the spark plugs at the wrong time.

Do you have any error codes in the ECU?

/Magnus F.

[slomove]

Found it...

Paul came along and we did the routine checks.
- plugs looking O.K. if a bit rich except the front plug looking more leanish
- compression: fine
- marked TDC and measured advance with timing light: was O.K. but a bit bouncy
- hooked up the PC and checked a few things in the ECU: TPS cal fine, pickup timing cal was a few degrees off but not substantial. Modified the somewhat strange ignition map around the idle position but no big difference.
- did the brake cleaner test with the TBs and noticed a change on cyl #1 but strangely when spraying around the front end (which does not make sense)

Finally Paul happened to look under the TB and noticed the #1 vacuum port spigot having no plug/nipple unlike the other TB barrels. These caps were not secured with cable ties and one probably blew off on back fire or just got brittle and fell off.

We capped the offending spigot and the problem went away.

[Doug Liedblad]

Gert

Are these the small black rubber caps over a small tube on the top of the TB?

The number one being hidden by the linkage a bit.

Next to the fine adjuster screw?


Doug

[slomove]

No, the one you mention on top belong (I believe) to the air bypass screws. They were all capped.

I mean the bigger 1/4" spigots coming out in 45 deg angle under the throttle body. Actually I don't have these on my Jenvey TBs. But they are convenient for balancing and I put such spigots for this purpose into the intake manifold.

Since we were messing with it anyway, I quickly hooked up the Carbtune and checked the barrel balance but this was on the money.

Gert