'97 OMC/VOLVO 5.7 GLI STARTUP CONDITION

[fisherman73]

I have owned this boat for approx 1 year and since I have had it it has an unusual startup cond. It runs very rich blows some black smoke and has some misfire due to the over rich condition. It act like it is in S.L.O.W. mode but both injectors are firing. It will cut the fuel off above 2500-3000 RPM. I have timed the period it will run like this and it is exactly 100 seconds every time. Then it will lean out and run beautifully untill the key is turned off, even if just for a second, and then restarted, then its back to 100 seconds of over rich and under 3k RPM

 

[Don S]

Re: '97 OMC/VOLVO 5.7 GLI STARTUP CONDITION

A 5.7GL is a carbed engine, not fuel injected.<br />A 5.7Gi or 5.7GSi is fuel injected.<br />If it is actually a GL model, it is probably flooding out when started because the choke is too tight. Give it some throttle to clear out the excess fuel.<br />A carbed engine doesn't start and stay running like EFI engines.

 

[fisherman73]

Re: '97 OMC/VOLVO 5.7 GLI STARTUP CONDITION

Thanks for the reply. Mine is a 97 5.7GLI which is a throttle body injected motor

 

[newport dave]

Re: '97 OMC/VOLVO 5.7 GLI STARTUP CONDITION

Sounds like it could be a bad Engine Coolant Temp (ECT)sensor. A bad ECT can trigger SLOW mode and it can cause rich condition. Not sure if it can cause both at the same time. <br /><br />Have you checked for trouble codes?<br /><br />Dave

 

[fisherman73]

Re: '97 OMC/VOLVO 5.7 GLI STARTUP CONDITION

I have actually replace the ECT sensor already. I have a code tool on order and should be able to find out if there are any codes later this week. <br />Aparently the only two conditions that will trigger s.l.o.w. mode are a grounded ect or oil pressure switch. I found that the oil pressure switch had become corroded and was not making any contact earlier today. I thought I was on to something but after the repair was done I had not changed anything.

 

[newport dave]

Re: '97 OMC/VOLVO 5.7 GLI STARTUP CONDITION

You don't really need to buy a code tool, you can use a 12volt LED and a paperclip to get the codes.<br /><br />Dave

 

[Don S]

Re: '97 OMC/VOLVO 5.7 GLI STARTUP CONDITION

Sorry, but here is no such thing as a 5.7GLI.

 

[fisherman73]

Re: '97 OMC/VOLVO 5.7 GLI STARTUP CONDITION

LOL Ok don I will take a picture of it in the morning and mail it to you. but just for repair purposes it is a 97 5.7 Tbi

 

[fisherman73]

Re: '97 OMC/VOLVO 5.7 GLI STARTUP CONDITION

You know I was thinking of doing the led and paper clip thing . but I thought it would be worth it just to have the ease of plugging the thing in. Knowing the trouble I get myself into I will need to read codes when Im stressed out and will screw it up.

 

[Reel Poor]

Re: '97 OMC/VOLVO 5.7 GLI STARTUP CONDITION

The MAT (manifold air temp) sensor will cause this problem also. This sensor is used for fuel enrichment on restart.

 

[fisherman73]

Re: '97 OMC/VOLVO 5.7 GLI STARTUP CONDITION

I think the air intake temp sensor is used only on multiport injection units. Mine does not have one anyway. Just MAP, ECT,and TPS

 

[Reel Poor]

Re: '97 OMC/VOLVO 5.7 GLI STARTUP CONDITION

Don might can give a little more info here. <br /><br />I do know Volvo did an add on change on the MAT sensor. They were adding one to engines that did not have them. These were on customer complaints of running rich.<br /><br />I have twin 2000 model 5.0Gi and both of them have MAT sensors.

 

[fisherman73]

Re: '97 OMC/VOLVO 5.7 GLI STARTUP CONDITION

are your 5.0s TBI units. If so Where is the MAT sensor located. <br />I think that because Volvo bought out OMC In '97 the only thing they did was some name changes from the OMC version. That probably has something to do with the strange GLI sticker that is on my motor.

 

[Reel Poor]

Re: '97 OMC/VOLVO 5.7 GLI STARTUP CONDITION

Yes, mine are TBI. The MAT sensors are mounted in the intake directly behind the throttle body. They are a two wire sensor and look alot like the CTS.

 

[Don S]

Re: '97 OMC/VOLVO 5.7 GLI STARTUP CONDITION

A large helping of CROW please, I did finally find a GLi model, it's a 5.7GLiPLKDCE. <br /><br />Did you check the oil pressure switch? That is the only other thing that would put your engine into SLOW mode. You should also notice one of the injectors shut off when it happens. Here is how SLOW is supposed to work.<br /><br />

 

[fisherman73]

Re: '97 OMC/VOLVO 5.7 GLI STARTUP CONDITION

Thanks Don, This is where I am confused, I did find a quite obvious problem with the oil pressure switch. It is located near the oil filter and due to corrosion it was disconnected and the switch was in terrible cond. So essentially it would have never grounded even with engine off. After replacing it no change was noted, and even grounding the switch manually would not create a change before or after it was running normally.But I was on muffs not under load. Im heading to the lake today so I will look at injector spray while under load.

 

[Don S]

Re: '97 OMC/VOLVO 5.7 GLI STARTUP CONDITION

Make sure the wire and the terminal on the wire is in good shape also. If the wire has high resistance, it's not going to work.<br />If the wire is too short after you cut it back to good wire, just splice (solder) a new section in with a new terminal end.

 

[fisherman73]

Re: '97 OMC/VOLVO 5.7 GLI STARTUP CONDITION

I couldnt find anything on it but I was wondering if maybe if the ecm doesnt recieve ground signal from the oil pressure switch with intially started then as a default it goes into s.l.o.w. mode for a period then will run normally. Is that where my 100 seconds is coming from? Also it is not clear but is an exceptionally rich cond also part of slow operation? It seems to make sense as making it rich could help cool it off if that was the cause of the mode.

 

[newport dave]

Re: '97 OMC/VOLVO 5.7 GLI STARTUP CONDITION

I was thinking that the ECT sensor was out of range (low temp) causing the rich condition, then the ECM would switch to using a default value after 100 seconds. Could not find anything in the manual to confirm this.<br /><br />Dave

 

[bigbrownbuku]

Re: '97 OMC/VOLVO 5.7 GLI STARTUP CONDITION

Originally posted by Reel Poor:<br /> Don might can give a little more info here. <br /><br />I do know Volvo did an add on change on the MAT sensor. They were adding one to engines that did not have them. These were on customer complaints of running rich.<br /><br />I have twin 2000 model 5.0Gi and both of them have MAT sensors.

ive only seen this addition on small block u.s. motors that cross my path. unless you have the exact latest ecu they are redundant. as far as i know only the 8.1's use the mat. <br /><br />on topic - when was your last injector service.