2.4S MFI Pump

Manipou · 02-10-2005, 11:16 AM

Is there any way to test a MFI pump? My 2.4S is running lumpy, timing is good as is plugs spark etc. It is almost like its running on 5 cylinders. Seems like its something to do with induction? Could the belt driving the pump have jumped teeth or something equally as simple? Help please....

Scott Clarke · Scott Clarke's Garage

Manipou-
There is a time-honored, much revered document known as "Check, Measure, and Adjust"(also refered to as "CMA"). Do a search with these terms and you should find a source for downloading it. It is a wonderful, step by step method of getting everything that could be wrong right, and that is quite a number of things. If you follow CMA you can then diagnose any remaining problem.
-Scott

Jim Richards · 02-10-2005, 12:04 PM

Follow the procedure faithfully. No short-cuts. No shot-gunning. In the end, you'll achieve MFI enlightenment.

Manipou · 02-10-2005, 01:14 PM

thanks guys

Bobboloo · Bobboloo's Garage

You can download it from Pelican in the tech articles section.

Manipou · 02-11-2005, 06:28 AM

Sorry to bother again. I am following the sequence as described but I have got to fuel pressure and flow, when I took the pipes off the top of the MFI pump and cranked the engine there was little fuel actually being pumped out, most only showed a few drips worth of fuel fuel and one didnt even show any sign of fuel. I expected the unit to squirt fuel out. Is there anywhere that states what pressure the unit should be pumping at. Does the unit sound knackered? Thanks

Tim Walsh · Tim Walsh's Garage

manipou,
If I remember my CMA correctly, it's refering to fuel pressure and flow before the MFI pump itself. The standard operating pressure for the lines AFTER the MFI pump is 16-18 bar, but when they're not hooked up to the injectors themselves you get very little flow and pressure.

Manipou · 02-11-2005, 07:06 AM

Oh I checked fuel flow before the pump as well, why does it not show pressure without the injectors connected?

Tim Walsh · Tim Walsh's Garage

While I have no proof on it I belive that the injector is spring loaded and the pump will only put out a tiny bit of fuel per injection, it seems as though there isn't any flow or pressure. Imagine a garden hose, it doesn't look like it has much pressure, but when you put your finger over the end it sprays out with alot more pressure.

Manipou · 02-11-2005, 09:10 AM

Yeah, good news is I have found the problem, the bad is that the MFI pump is not working properly. 2 pistons are not moving and looks like one has some components broken. Does anyone know who can fix these or if spare parts are available. Im in the UK.

Also off subject what engines came with the 7R Mag case, did the later 2.7 engines have them too? Thanks

Tim Walsh · Tim Walsh's Garage

THere are a few places around that fix them. Gus at pacific fuel injection, Hans at H&R fuel injection in NY and Henry Schmit at supertec in SoCal. All are highly recommended.

The late 73 2.4's had the 7R case as did all the 2.7 engines.

Manipou · 02-11-2005, 09:32 AM

So even the late 2.7CIS motors had them? are they exactly the same? I thought I had read that the later cases suffered from overheating hence not recommended for 2.7RS engine conversions?

Tim Walsh · Tim Walsh's Garage

Yes, all the 2.7CIS motors had them. THe later motors had thermal reactors installed on them that greatly increased the operating temperature. That's what killed the later 2.7's. The 2.7RS and the 74 2.7 both used the normal heat exchangers that the earlier cars used and neither suffered from (as much) case warping.

The 2.4 cases are slightly different. The spigot bore was smaller to accomodate the 84mm cylinders.