1988 740gle non turbo

cudajeff · Post by **cudajeff** » 04 Apr 2012, 09:36

i have a 1988 740gle non turbo starts and idles o.k. but when you depress accelerator it had no power 2000 rpm max.

it seemed like fuel delivery to me so i changed fuel filter while under i listened to fuel pump it did not make a sound so i replaced it too.i also changed dist. cap rotor wires and plugs due to the green on the end of wires and top of cap. none of this helped.

i then pulled the gas line before the second pump tried to crank only got the siphon effect not pumping so i changed that pump. no help but it is pumping gas now, checked after both pumps an filter, also opened line at fuel rail had lots of pressure not sure how much.

after all this when i started it it was no better but after letting it run about 2 minutes the catalitac convertor got very hot and the pipe behind it wasant very warm at all. i did have plenty of exhaust out tail pipe(not sure if plugged means plugged). so i broke the union apart before the cat now if i let it run i can eventually get the rpms up but it takes a while when you accelerate,i mean push gas to floor it takes like 5 sec to get to 5000 rpm let off same thing each time you push the gas.

it has 215000 miles but i have only had it 4 months and was told it had been rebuilt.also when i changed fuel pumps i did have 12v to each one.

Post by **JDS60R** » 04 Apr 2012, 10:20

Welcome Jeff !!

Post by **billofdurham** » 05 Apr 2012, 12:32

Welcome to Matthew's Volvo Site.

Check the connector to the Mass Airflow (MAF) sensor. Disconnect it and ensure that all of the pins are fully seated in the plug. Check that there are no air leaks between the MAF and the throttle body. You can clean the MAF with a cleaner specifically for that purpose.

Check the air filter for any blockage. If it is very dirty replace it. One problem that did surface on the 740 air filter housing was breakdown of the foam in the air filter box. This can cause a blockage of the MAF.

Bill.

cudajeff · Post by **cudajeff** » 05 Apr 2012, 19:32

checked connections on maf looked good. got the maf cleaner an cleaned,when i bought the car the air box hand been swapped out with a cone type air cleaner. the tube to the throttle body was free of debris but there was a slight amount of oil i cleaned it out and made sure it was sealed at all the connections.actually seemed a little better but not real good has a hard time from about 1000 rpm till 2500 then sounds ok above that.i did reset the timing also no change. should i hook the exhaust system back up i have been trying it with it unhooked since it got hot that day from the flange before the cat back.it also will not go above 1000 15000 rpm at all until after its ran 4 a minute or so.