Our Bahia Red '72 lacks mid range power and would like to throw this question out the members. Any thoughts as to what is causing this? Acceleration seems fine until we start to climb in RPM's then it seems to level off. Next shift adds some power but hitting higher RPM's seems to level off again? It runs fine other wise.

Some friends suggested timing and that looks logical. How about it guys, any suggestions?

Thanks in advance!

Keoni914

Carbs( what kind and size) or F.I. ? Dave

Dave, Stock FI, 1.7

..............water in the gas tank....fuel delivery...1)fuel filter...2)fuel pump...3)fuel line kinked...check and replace if older anyway.....Ignition Timing...Distributor, advance mechanism is not properly working....(you used the wrong timing mark on the fan...ignition timing is too low)...lousy gas..too low a octane......(for starters).

I'm thinking the culprit would be ignition timing. Are there any How-To's here on that? How about the valve adjustments?? Could that be another cause? Or THE cause?

Keoni914

..................Thats entirely possable....NOTE HOWEVER that you really have not given much information about your particular engine..1) age, 2)carbs or injection 3)specifications about the engine. 4) all information helps as what and how it,s constructed will make a difference in prioritising solutions to the fix.

What rmp is your "mid range"? How long ya had the car? How old is the engine? Has it always ran like this? Have you done anything that ME733 has spoke of? It could be any or all of those things . Info please!

Sure this is not just a case of the 1.7s?

It's a stock FI 1.7, 1972. 98k miles

The RPM range that I notice the loss of mid range power is around 3800 to 4000. I have the car about a year and previous owner didn't mention anything unusual. (Yeah right!)

It's not the gas and we replaced the fuel filter last year with an OEM type.

Thanks for being so patient!

Keoni914

Yo Man, do you mean this problem is with all 1.7's???

Keoni914

check fuel pressure (if possible run a temperary hose to check under actual load). how is your air filter? how do your plugs read?

check & confirm timing. i've heard from several that thier acual timing marks where way off, that while building their engine they checked piston TDC to marks... any dought experiment with different timing/driving to see if this could be an issue.

Not a fresh build, but a tired old 1.7 maybe. Have you done a compression check?

Does it do oaky over 4000? Does it keep pulling to 5000?

Have you checked the timing? How bout a recent full tune up?

I was just making jokes that 1.7s are kinda low on the power scale to begin with, and your expectations may have been higher - especially if you had not driven one of these cars before and were expecting modern sports car performance.

Assuming that there is a problem, you need to do some basic diagnostics. Check your valves. Then check timing and dwell. Then get the engine warm and check compression (compression testers are cheap, and give you a quick window into the overall health of the engine. Engine must be warmed up, plugs removed, and throttle open.) All of these are cumulative, so checking compression without checking valves may give you a false reading.

When you get to tunging the FI, I am out of my league. But my guess is that the valves have not been checked for a long, long time. Timing may have been checked more recently, but could still be off - same for dwell. maybe you need new plugs and wires. Its all very basic stuff that we can never trust that a PO has ever done or even known to do.

For the year that you have had the car, has it always done this?
Have you done any of the basic maintenance these cars require? I'm not busting balls, many owners are simply never aware that they need to do this stuff every now and again. Over time, little variances add up to noticeable problems.

Zach

Wow, all very good tips, and I thank you all! I'll get busy!!


Huge thanks for taking the time to help me, I appreciate it!!

Keoni914

.........KENOI914..........I,m SURE all of us hope you will report back when the problem(s) are found and resolved............remember this.you said:"I replaced the fuel filter a year ago"....water in the fuel is a by-product/problem, of ALCOHOL in the gas. MOST ALL fuel filters will not flow WATER, AND WATER will clog up the fuel filter/ restrict fuel flow...You may have correct pressure, but low VOLUME.....try some very high quality water remover additive...drive it some ...see what happens.. IF you get lots of condensation out the tail pipe....dripping water...you will have at least a part of the problem(s). resolved.