Hello All -

I have been driving with an issue for the last week. Not sure if this is fuel, tranny or vacuum related. When driving at varying speeds usually over 70 on the highway, I lose speed and can't get any faster when I hit an incline or go over a hill.

I know I have some vacuum issues already (no power locks), but the car does shut off normally. I do notice when I first start off in the morning also, that it takes a minute or 3 before the car will engage in reverse.

Not sure if those issues are related or not. Not sure if its serious or not. Thanks!! This is on my 81 300D.

 

Fuel level does not matter. It happens anytime.

 

Anyone?

 

Does engine RPM increase on the incline but there is no increase in speed? Could be the tranny is slipping? First, checkthe fluid level in the tranny and the condition of the tranny filter? Vacuum haslittle relationship togear engagement.Be sure you don't have a fuel/or airleak at the inlet to the fuel pump. On these non-turbo cars the inlet pump does wear out and will result in reduced fuel flow under heavy load.

 

Well I am 'Grateful' for your reply. The car does not have an increase in RPM. You put it to the floor and nothing really happens. You slowly slowdown. I am pretty sure I have some form of a tranny problem. I honestly fear that if I drop that tranny pan, anything holding the tranny together would shake loose. What type of tranny fluid does the car use? Straight ATF?

The fluid level did look ok. Where is the fuel pump on this? I checked the hoses over the weekend and everything seemed tight. Where is the inlet pump. I do have a non-turbo. costly repair?

Again.. thanks for the reply!

 

Dextron Mercon II was the baseline fluid but is no longer available. Use Dex/Merc III. I get mine at Wally World by the gallon. Make sure and drain the torque converter too if your thinking about a filter change. About 7 qts for a complete drain and fill. Did the fluid smell burnt or look dark brown instead of red?
The fuel pump is about thesize of a fist and is mounted on the injection pump. The primer and primary fuelfilter are connected to the pump. I'd look for leaks at the fuellines orthe stream of air bubbles in the primary filter. The stream is from a leaking primer and usually means the primer doesn't work. I have patched the old style primers by unscrewing the plunger and cleaning it with acetone then squirtingRTV around the plunger and pushing itback in. The primer willnever work again anyway because of theair leak and this allows a delay in replacement until filter replacement is required.

 

Have you pulled the prefilter and inspected it and also make sure the primer valve is not leaking? On an 81 300D the prefilter looked clean with only a small amount of dead algae on the inside. The engine would not make power above 55 mph. Thought the pump was shot and there had to be a leak at the pump. Finally pulled the filter and saw it was completly plugged with dead algae. The design of the prefilter prevents you from actually seeing if the filter is blocked. New filter and problem was solved. Let us know if there are any leaks, anywhere; secondary filter, injectors.

 

Thanks for the reply. I will check that out over the weekend. It would be the first chance I get to look at it. I will report back my findings.

Thanks again.