This applies to and may refernce a post I made on Saturday afternoon but I thought a new audience would give me insite into the reasons behind the potential fixes.

Background...
The car stopped starting. It crank, sometimes start for a second or two and then die, it can't hold an idle. I tried cleaning the throttle body and that didn't work, evryone pointed towards vacuum leak.

Here comes the question...some of the hoses that have been suggested as culprits of my problems I don't understand how they would affect my starting. One was the vacuum hose that goes from the AMM to the TB. There isn't a vacuum hose that goes from the AMM to anywhere. Should there be? Another suggestion was that the plastic intake tube from the TB to the AMM might be cracked. Why would this affect starting? I me still be in carborater mode from my highschool days with a 63 chevy nova with a 350 small block in it but shouldn't the car run with an open TB? Iguess I understand the vacuum system better on that chevy then I do I the volvo. any help would be appreiated.

Ken
--
1987 240 dl wagon 'rustbucket'

OK, so if it's this hose, and, again, I haven't been able to check, perhaps the brief starts I was getting was due to the repeated introduction of fuel into the combustion chamber and when the chamber finally had enough gas, whamo, the thing started. But, since the computer was improperly mixing the fuel then as soon as the excess fuel was burnt off, the car would die. Does this sound reasonable? I can't wait to see if this is the problem, maybe I'll head home at lunch!
--
1987 240 dl wagon 'rustbucket'

I don't know if you made any progress with this yet or not, but the other posts are exactly right. Any air leak introduces excess unmetered air into the engine. The ECU will compensate some based on what the O2 sensor says the end result is, but assuming you've got a typical level of leakage at the intake, and assorted vacuum hoses, and then you throw a pretty significant leak from the air hose into the equation, you've got a pretty good source for your no-start condition.

To test this as the possible solution, try just wrapping that big hose in duct tape to seal it up. If that cures it, plan on getting a new one before too long. FCP Groton sells this:
Air Intake Hose B2000-27092 Scan-Tech Production $19.63
If nothign else this hose leaking will cause radical idle speed irregularities.
--
Rob Bareiss, New London CT ::: 86 244DL, 87 244DL, 88 744GLE: 625K total

If the duct from the AMM to the TB is cracked, it means that the car will be adjusting the mixture not according to the amount of air moving as measured by the AMM but that amount of air plus what's leaking into the duct. This will adversely affect the mixture that the ECU ultimately decides is correct. Presumbably you'd end up with a lean idle, since the ECU would be supplying gas based only on what the AMM said should be the case. If the duct leak were large enough, the AMM would call for very little fuel since very little air would be going through the AMM. If the discrepancy were large enough, maybe there would not be enough fuel in the mixture to support combustion. In the meantime, the coldstart injector would be giving you enough unmetered gas to get the car started and running for a second or two.

Don't know about vacuum hose from AMM to TB. Never saw that, but that doesn't mean it can't exist on _some_ cars...

Others may explain this better, but, here goes... the AMM measure the amount of air entering the intake, it then adjusts the amount of fuel accordingly, commonly know as mixture. Any leak between the AMM and the TB, (after the air has been metered) will lean out your mixture. If the leak is large enough, the mixture will get sooo lean (lots of air, very little fuel) that it may not keep running, or will idle very poorly.

Experts, did I get that right?

Matt

--
'82 DL - 150k, '93 945 - 96k